Life Points are the "health" left for a player while playing the game. An official Duel starts with 8000 Life Points for each player, although sometimes players play with more or less depending on the situation. If the player's Life Points deplete to 0, the player loses. Once a player gets to 0 Life Points, they cannot get lower and have negative Life Points. Other common amounts are 4000 and 2000 Life Points (4000 is the most common amount used in the various anime series, while 2000 was used during Duelist Kingdom tournament in the Yu-Gi-Oh!, or even 16000, offered in some video games. It is not uncommon for some players to use the unofficial rule of 4000 Life Points for a quick, casual Duel. This is sometimes known as a "Half-Duel." In the anime and some video games, there are some conditions where a player cannot lose the Duel. One example is if you have two or more cards in your hand, including "Infernity Zero" (whose effect will let you stay in the game, even though your Life Points are at 0). Also, there are times when both players Life Points reach 0 (this is considered a draw, with neither having won).

Losing Life Points can be caused by the following:

• One of your Attack Position monster attacks/is attacked by a monster with a higher ATK, in which case, the difference is dealt to you as Battle Damage.
• Attacking a Defense Position monster that has a higher DEF than the ATK of the monster you are attacking with, the difference is dealt to you as Battle Damage.
• Paying a cost for a card such as. "Brain Control".
• Piercing damage (which is also counted as "Battle Damage") such as "Mad Archfiend" or "Ancient Gear Golem".
• Effect Damage Spell, Trap, or Effect Monster effects, such as "Ookazi".
• Getting attacked by a monster directly in a direct attack, in which case, the damage you take is equal to that monster's ATK.