5-Card Omaha (Big O): The Action-Packed Five-Card PLO Variant
What Is 5-Card Omaha (Big O)?
5-Card Omaha, widely known as "Big O" in American card rooms, takes the already action-packed nature of Pot-Limit Omaha and amplifies it by dealing each player five hole cards instead of four. This seemingly small change—one extra card—fundamentally transforms the game's dynamics, creating even more draws, closer equities, and substantially larger pots than standard PLO.
The game follows all standard Omaha rules: you must use exactly two of your hole cards combined with exactly three community cards to make your final five-card hand. However, with five hole cards instead of four, you now have ten possible two-card combinations to work with (compared to six in standard PLO), dramatically increasing the likelihood of flopping strong hands and powerful draws.
Big O is most commonly played as a Hi-Lo split game (also called "Big O 8" or "5-Card PLO8"), where the pot is divided between the best high hand and the best qualifying low hand (eight-or-better). According to Card Player Magazine, this format has become increasingly popular in mixed games and card room rotations, particularly in the Southern United States where the game earned its "Big O" nickname.
The high-only version (5-Card PLO or PLO5) is less common but offers even more action, as players can focus entirely on making powerful high hands without splitting pots. Both versions require substantial adjustments from standard 4-card Omaha strategy.
The Fundamental Rule: Still Exactly Two Hole Cards
Despite having five cards in hand, the core Omaha rule remains unchanged: you must use exactly two cards from your hand and exactly three from the board to construct your final five-card poker hand. You cannot use three or four of your hole cards, even when it would make a stronger hand. This rule catches many new players off guard, especially those transitioning from Texas Hold'em.
With five hole cards generating ten possible two-card combinations (compared to six in standard PLO), board reading becomes significantly more complex. You're evaluating many more potential hands simultaneously, making accurate hand assessment crucial.
Big O Examples: The Two-Card Rule in Action
Example 1 - The Flush Confusion: You hold A♠ K♠ Q♠ J♦ 10♣. The board shows 9♠ 7♠ 5♠ 3♥ 2♦. With three spades in hand, you might think you have a flush. You don't. You can only use two hole cards, so you'd need exactly two spades from your hand plus three spades from the board. Using A♠ K♠ from your hand with 9♠ 7♠ 5♠ gives you an Ace-high flush. Your Q♠ doesn't help—it's the third spade that can't be used.
Example 2 - The Low Hand Trap: In Big O Hi-Lo, you hold A♣ 2♦ 3♥ 4♠ K♠. The board shows 5♦ 6♣ 8♥ J♠ Q♦. You might think you have a fantastic low with A-2-3-4 in hand plus the 5-6 on board. But you can only use two hole cards. Your best low uses A-2 from your hand with 5-6-8 from the board for an 8-6-5-2-A low. If you had hoped to use A-2-3, that's three cards—not allowed.
Example 3 - The Full House Miss: You hold K♥ K♦ K♣ 9♠ 8♠. The board shows K♠ 7♥ 7♦ 5♣ 2♥. Four Kings! Amazing, right? Wrong. You can only use two Kings from your hand, giving you K-K-K-7-7 (full house, Kings over Sevens). You don't have quads—you have a full house.
How Big O Plays: Complete Game Flow
Setup and Blinds
Big O uses the standard button and blind structure. The dealer button rotates clockwise, with the two players to the left posting small and big blinds. These forced bets create the initial pot before any cards are dealt.
The Deal: Five Hole Cards
Each player receives five cards face down, dealt one at a time starting from the small blind. These are your private hole cards. With five cards, the number of possible final hands you can make increases dramatically, making starting hand selection both more nuanced and more critical than in standard PLO.
Pre-Flop Betting
Action begins with the player to the left of the big blind (under the gun). In Pot-Limit format, the maximum raise is the size of the pot after calling. Pre-flop action in Big O tends to be even more multi-way than standard PLO—with five cards, more hands have potential, leading to larger pots going to the flop.
The Flop, Turn, and River
Community cards work identically to other community card games: three flop cards, one turn card, one river card dealt face up. Betting rounds follow each community card, with action starting from the first active player to the left of the button.
Post-flop play in Big O is where complexity explodes. With ten two-card combinations available, you're frequently evaluating multiple made hands and draws simultaneously. Combination draws with 20+ outs are common, making pot-limit betting essential to prevent hands from simply getting all-in pre-flop.
Showdown and Pot Division (Hi-Lo)
In Big O Hi-Lo, the pot is split between the best high hand and the best qualifying low hand at showdown. To qualify for low, you must make a five-card hand with all cards 8 or lower, with no pairs. If no player has a qualifying low, the entire pot goes to the high hand. Players can win both halves ("scoop") if they have both the best high and best low, or even use different two-card combinations from their hand for high and low.
Big O Starting Hand Selection
Starting hand selection in 5-Card Omaha requires evaluating how all five cards work together. Premium hands feature maximum coordination—every card contributes to making strong hands. According to Two Plus Two poker strategy forums, the additional hole card makes coordination even more valuable than in standard PLO.
Premium Big O Hi-Lo Starting Hands
A-2-3-4-5 double suited: The dream hand in Big O Hi-Lo. You have the nut low draw in multiple configurations, wheel potential, and a straight flush draw. This hand can scoop monster pots by making both nut low and a straight or flush for high.
A-A-2-3-K double suited: Premium pair with nut low backup and high card strength. The Aces can make top set for high, while A-2-3 provides nut low potential. Double suitedness adds flush draws in two directions.
A-2-3-K-K suited with A: Combines nut low potential (A-2-3) with premium high pair (K-K) and nut flush draw. This hand can scoop by making a low with A-2 while Kings make top set for high.
Premium Big O High-Only Starting Hands
A-A-K-K-Q double suited: The gold standard for PLO5 high. You have two premium pairs, nut flush potential in two suits, and Broadway straight possibilities. This hand dominates pre-flop and flops well frequently.
K-Q-J-10-9 double suited: Pure connectivity for straights with flush backup. This rundown can make multiple nut straights and has considerable flush equity when double-suited.
A-K-Q-J-10 suited with Ace: Broadway rundown with nut flush draw. Makes the nut straight with many boards and has top flush potential.
What Makes a Good Big O Hand
Full Coordination: All five cards should work together. A-2-3-4-J is weaker than A-2-3-4-5 because the Jack doesn't connect with the low cards. Every "dangler" (disconnected card) reduces your hand's potential. For more on hand evaluation principles, see our poker hand rankings guide.
Double or Triple Suitedness: Having cards in multiple suits gives flush potential in several directions. A hand with A♠-2♠-3♥-4♥-5♦ has flush draws in two suits, vastly superior to five cards in four different suits.
High-Low Potential: In Hi-Lo, hands that can win both ways are most valuable. A-2-3-4-5 suited can make the nut low (A-2-3-4-5 with three board cards) and a straight for high simultaneously.
Nut Potential: You want hands that make the nuts when they hit. Having an Ace for nut flush draws, A-2 for nut low draws, or connected cards for nut straight possibilities is essential. Second-best hands lose massive pots in Big O.
Hands to Avoid in Big O
A-A-9-8-3 rainbow: Despite the Aces, this hand is problematic. The 9-8-3 provides minimal coordination—no low potential, limited straight draws, no flush draws. Your Aces must hit a set to be strong, and even then, you're vulnerable to straights and flushes.
K-Q-6-5-2 rainbow: Disconnected high cards (K-Q) paired with disconnected low cards (6-5-2) create a hand that does nothing well. You can't make nut low (no Ace), your straight potential is limited, and no flush draws exist.
Four or five cards of the same suit: Counterintuitively, this is bad. You can only use two cards, so having four spades means two are wasted. You'd rather have cards distributed across 2-3 suits with better connectivity.
Big O Strategy Fundamentals
The Nut Imperative is Even Stronger
If standard PLO requires playing for the nuts, Big O demands it. With ten possible two-card combinations per player, the likelihood that someone has the nuts or near-nuts is extremely high by the river. Second-best flushes, non-nut straights, and underfull houses lose massive pots. Your primary focus should always be: "Can I make the nuts, and do I have the nuts now?"
Scoop Potential in Hi-Lo
In Big O Hi-Lo, hands that can win both high and low are exponentially more valuable than hands that can only win half. If you have the nut low locked with A-2 and can also make a straight or flush for high, you're playing to win the entire pot. Hands that can only win one way often get quartered (splitting half the pot with another player holding the same hand), making them marginally profitable at best.
Protect Your Low Draws
In Hi-Lo, getting "counterfeited" on your low draw is devastating. If you have A-2 for a nut low draw and the board pairs a low card you were using, your low is ruined. Having backup low cards (A-2-3 or A-2-4) protects against counterfeiting. This is why hands like A-2-3-4-x are so powerful—multiple low combinations provide redundancy.
Position Matters Tremendously
With more combinations and draws to evaluate, acting last provides enormous advantages. You see what opponents do before committing chips, allowing you to make more informed decisions. Late position allows you to steal pots when opponents show weakness and extract maximum value when you have the nuts. Our position strategy guide covers these dynamics in detail.
Variance and Bankroll Requirements
Big O has even higher variance than standard PLO, which itself has higher variance than Hold'em. Closer equities pre-flop mean bad beats happen more frequently—you'll often get money in good and lose, or get it in bad and win. The PokerNews strategy section recommends maintaining 50+ buy-ins for Big O compared to 30-40 for standard PLO. Emotional resilience is essential.
Reading Boards for High and Low
In Hi-Lo, you must constantly track both the nut high and nut low possibilities. On a board of 8-5-3-K-Q, the nut low is A-2 (making 8-5-3-2-A), while the nut high could be a set of Kings, a straight, or potentially a flush if suited cards appeared. You may need to use different two-card combinations for high and low, adding another layer of complexity.
Big O vs Standard 4-Card PLO: Key Differences
More Combinations, Closer Equities
The fifth card gives each player ten two-card combinations instead of six. This means more potential hands, more draws hitting, and pre-flop equities running even closer than in standard PLO. Hands that are 60/40 favorites in PLO might be 55/45 in Big O, increasing variance and making pot-limit betting even more appropriate.
Multi-Way Pots Are More Common
With five cards, more starting hands have potential, leading to more players seeing flops. Multi-way pots are the norm rather than the exception. This affects strategy significantly—bluffing becomes less effective when facing three or four opponents, and hand values must be stronger to continue.
Drawing Hands Are Even Stronger
Wrap draws and combination draws with 20+ outs are more common in Big O. A hand might have a straight draw, flush draw, and low draw simultaneously, making it a favorite against many made hands. This is why pot-limit betting is essential—unlimited betting would result in massive pre-flop all-ins with minimal skill edges.
Nut Potential Becomes More Critical
If the nuts matter in PLO, they matter even more in Big O. With more combinations in play, someone having the nuts is more likely at any given showdown. Calling large bets with second-best hands is a recipe for disaster. Your hands must have nut potential to be worth playing aggressively.
Hi-Lo Split Changes Everything
While standard PLO is almost always played high-only, Big O is predominantly a Hi-Lo split game. This fundamentally changes hand values—hands that can scoop both ways become premium, while hands that can only win one direction become marginal. Getting quartered (winning only 1/4 of the pot by tying for low or high) is a common pitfall.
Common Big O Mistakes to Avoid
Playing One-Way Hands in Hi-Lo: Hands like K-Q-J-10-9 with no low potential can only win half the pot. Meanwhile, opponents with A-2 hands are freerolling for the low. In Hi-Lo, hands must have potential to win both ways to be truly premium. Research from the UNLV Center for Gaming Research shows split-pot games favor hands with multi-directional winning potential.
Overvaluing Aces Without Backup: A-A-K-9-7 rainbow looks strong but plays poorly. The Aces need support—low cards for Hi-Lo low potential, suited cards for flush draws, or connected cards for straight possibilities. Naked Aces get cracked constantly.
Ignoring Counterfeiting Risk: Having A-2 for a nut low draw is excellent, but if the board pairs your low card, you're counterfeited. Hands like A-2-3 or A-2-4 provide protection—if your 3 is counterfeited, you still have A-2-4 for a backup low. Always consider counterfeiting risk when evaluating low draws.
Betting Non-Nut Hands Aggressively: Second-nut flush, second-nut straight, or an 8-low in Hi-Lo often lose to better hands. Big O generates massive pots, and being second-best costs you dearly. When facing significant action, ask yourself honestly: "Could my opponent have better?"
Playing Too Many Hands Pre-Flop: Yes, five-card hands have more potential than four-card hands. No, that doesn't mean playing K-J-9-4-2 rainbow. Uncoordinated hands remain uncoordinated regardless of how many cards you have. Discipline in starting hand selection is crucial.
Misreading Multi-Way Boards: With three or four opponents, someone having the nuts is highly likely. Don't overcommit with vulnerable made hands in multi-way pots. The more opponents, the stronger your hand needs to be.
Where to Play Big O
Card Rooms: Big O is particularly popular in Southern U.S. card rooms, where it originated and earned its nickname. Many casinos spread Big O as a regular game, typically in pot-limit Hi-Lo format with stakes ranging from $2/$5 to $25/$50. The American Gaming Association reports steady growth in Omaha variant offerings at commercial card rooms.
Home Games: Big O is increasingly popular in home game rotations. If your home game currently plays PLO or mixed games, adding Big O provides variety and extra action. The Hi-Lo split format creates interesting dynamics where multiple players can feel they have good hands, building larger pots.
Online Poker: Several online poker sites offer 5-Card Omaha in various formats. Availability depends on your jurisdiction and the specific platform. High-only PLO5 and Hi-Lo versions both exist online, though player pools are smaller than for standard PLO or Hold'em.
Mixed Games: Big O appears in some mixed game rotations, particularly those focused on Omaha variants. Home games might include it in "dealer's choice" nights, and some casinos spread mixed games that incorporate Big O alongside other Omaha variants.
Related Poker Variants
If you enjoy Big O's action, consider exploring other Omaha variants. Standard PLO (4-card) offers similar action with slightly less complexity, making it an excellent stepping stone to Big O. The core concepts transfer directly—hand selection, nut focus, and draw evaluation remain paramount.
Omaha Hi-Lo (4-card) teaches the split-pot concepts essential for Big O Hi-Lo success. Understanding low hand qualification, counterfeiting, and scoop potential in the four-card version prepares you for the additional complexity of five cards.
For players who find Omaha variants appealing, HORSE mixed games and the 8-Game rotation include Omaha Hi-Lo, building versatility across poker formats. The strategic concepts—position, nut focus, pot odds—translate across all Omaha games.
Use our pot odds calculator to practice evaluating drawing situations. Big O presents complex multi-draw scenarios where understanding pot odds versus drawing odds is essential for making profitable decisions.
Responsible Big O Play
Big O's high variance and large pots create significant bankroll swings. Even skilled players experience extended losing periods simply due to the mathematical nature of the game. Never play stakes where losing several buy-ins would cause financial stress. Proper bankroll management—50+ buy-ins for Big O compared to 20-30 for Hold'em—provides the cushion needed to weather inevitable downswings.
The game's action-heavy nature can be psychologically compelling. Larger pots, more draws, and frequent close decisions create excitement that some players find difficult to manage. Setting strict session limits, taking breaks, and maintaining emotional discipline are essential for long-term success and enjoyment.
If poker play is causing financial hardship, relationship problems, or emotional distress, seek help immediately. The National Council on Problem Gambling provides confidential resources for those struggling with gambling-related issues. Big O should be an entertaining intellectual challenge—never a source of harm.
Frequently Asked Questions
What does "Big O" stand for?
"Big O" is simply a nickname for 5-Card Omaha, particularly the Hi-Lo split version. The name originated in Southern U.S. card rooms and distinguishes the game from standard 4-card Omaha. The "Big" refers to the extra (fifth) hole card.
Can I play the board in Big O?
No. Like all Omaha variants, you must use exactly two cards from your hand combined with exactly three from the board. You cannot use all five board cards ("play the board") as you sometimes can in Texas Hold'em.
Is Big O always played as Hi-Lo?
Not always, but Hi-Lo is the dominant format. High-only 5-Card Omaha (PLO5) exists and offers even more action since there's no pot splitting. However, Big O Hi-Lo is far more common in card rooms and home games.
Why is pot-limit the standard betting format?
With five hole cards creating ten possible combinations per player, hands run extremely close in equity pre-flop. No-Limit would result in frequent all-ins before the flop with minimal skill edges. Pot-limit betting allows the game to develop post-flop where skill can influence outcomes.
How does Big O compare to Courchevel?
Courchevel is another 5-card Omaha variant where the first community card (flop card) is dealt face-up before the pre-flop betting round. This creates different strategic considerations than Big O, where all community cards come after pre-flop action. Both games use five hole cards with the two-card rule.