Bomb defusal is the most popular of the two "classic" game modes (the other being hostage rescue) and it's pretty much the go-to game mode for anybody looking to play Counter-Strike. In this game mode, the Terrorists must plant a bomb at one of two bomb sites (which are typically close to CT spawn), and the Counter-Terrorists must stop them.

Terrorists win if they eliminate all enemies or plant the bomb before the round ends and it explodes (which takes 45 seconds; it doesn't need to explode before the round time ends but it needs to be planted). Counter-Terrorists win if they eliminate all enemies, defuse the bomb (which takes 10 seconds without defuse kit/5 seconds with defuse kit) or if round time expires before the bomb is planted.

It's regarded as the most balanced game mode in terms of winnability for both sides, and for that reason it is the only game mode in the Active Duty map list (see Maps page for more info). Because it is "classic," it can be played in both Casual and Competitive games.

Hostage rescue is the other "classic" game mode in CS:GO. In this game mode, the Terrorists must protect the hostages near their spawn, and the Counter-Terrorists must carry at least one of the hostages and take them back to one of the designated "hostage rescue zones" (which are usually located near CT spawn). Hostages cannot be killed, but players on both sides will lose money if they hurt a hostage.

Terrorists win if they eliminate all enemies or if round time expires before a hostage is rescued. Counter-Terrorists win if they eliminate all enemies or rescue at least one of the hostages.

This game mode is generally regarded as less balanced than bomb defusal, as the Counter-Terrorists' equipment makes them less suited for offensive attacks (most CT weapons are balanced towards being defensive and slowing the enemy down, compared to their higher-damage T counterparts), among other reasons. Because it is "classic," it can be played in both Casual and Competitive games.

Officially included in the Counter-Strike series for the first time with CS:GO, deathmatch is a game mode that evolved from a popular community-made custom game mode for earlier games in the series. It's a basic team deathmatch setting that is played on either Active Duty or Reserves maps (depending on the server) and it's a great way to warm up your game and your aim against real opponents.

Players infinitely respawn with armor randomly across the map and can select any weapon for free (minus grenades and weapons unavailable to the player's current team). The only objective is to get as many points as possible before the round ends (typically 10 minutes). Some weapons give more points than others

Counter-Strike: Global Offensive is the first Counter-Strike game to include a built-in competitive mode to appeal to the professional and competitive player by being structured similarly to professional tournament play, including swapping sides, friendly fire, and locked teams.

Unlike casual mode, competitive mode always pits two teams of 5 against each other in a 30 round match. The roundtime is 1 minute 55 seconds and the bomb timer is 40 seconds. It is not possible to switch sides during the game except at the halftime. After the first 15 rounds, the game reaches halftime and the two teams will switch sides. The first team to score 16 points wins the game. If both teams score a total of 15 points by the end of the 30th round, the match will end in a tie. If the player has a rank then they are revealed to all players when the match has ended. Games can also end prematurely if one team surrenders to the other. A vote to surrender must be unanimously agreed upon, and the vote is locked until a team member abandons the match.

Additionally, players are required to have a profile rank of at least Private Rank 2 to be eligible for competitive matchmaking.