The fist is the player's stock melee attack. It is always available unless the player has picked up a chainsaw. Punching is only about as effective as a pistol shot, however, unless the player has collected a berserk powerup, which increases the power of the fists tenfold. Like the pistol, the punch is used via left hand.
- In the PlayStation and Saturn ports of Doom, the player can still access the fist attack even if he picks up a chainsaw and regardless of whether he has also picked up a Berserk Pack. This feature is also available in Doom 64.
- When wielding weapons, the protagonist's hands are shown to be wearing brown gloves (black in Doom's title screen). When punching, the player's right hand is unadorned, while his left hand carries a spiked knuckleduster.
- Since monsters are technically activated by any nearby attacks from players and not specifically by the sound effects of these, a punch in the air will alert them as if it were a loud gunshot. Players who want to provoke enemies without wasting ammo can do so with the fist attack.
- The fist from Doom 64 went through some graphical changes. The protagonist now wears brown, bloodstained gloves and lacks the knuckleduster.
- In the Game Boy Advance port of Doom, if the player punches a wall the same "hitting" sound effect (as if the player had punched an enemy or barrel) will be heard.
- The Xbox Live Arcade release of Doom II features an Achievement that requires the player to kill a Cyberdemon with their bare hands, named "You Have Huge Guts", after the Doom comic. Note that the player is required to use the fist only to kill a Cyberdemon: players can use other weapons to soften the Cyberdemon up and earn this achievement as long as they use the fist to deliver the final blow. This also appears as a trophy in the PlayStation 3 version of Doom Classic Complete, under the name "Knuckle Sammich".
- In Brutal Doom, both of the player's hands wear black fingerless motorcyclist gloves without knuckledusters and become blood-stained after killing an enemy via punch or chainsaw. The punches are now much more accurate and useful - the primary fire key throws a fast left jab while the secondary fire key throws a slower but more powerful right cross punch - and can perform fatality-style finishers on enemies or simply gib them after acquiring the berserk object or a demonic strength rune - the berserk power is noted by the punching sound effect becoming "bolder" and deeper. Pressing the reload key after getting the berserk/demon rune alternates between "smash" (for gibbing monsters) and "rip and tear" (for the finishers) modes. And unlike the original fist, it will not alert monsters when you punch in the air.