Punch Balls are items appearing only in Punch Ball Mario Bros. They are red and green stone spheres that can be thrown at enemies, resulting in them being stunned and allowing Mario or Luigi to walk over and defeat them. A Punch Ball's range is not very far, and it makes one small bounce after hitting the floor. If the POW is activated while it is on the floor, it will bounce twice. The balls must be retrieved after every throw, even after the player loses a life. If the ball falls into the bottom pipe, it will respawn on the POW. If there is no POW, it will fall to the lowest floating platform. It is impossible to throw and jump at the same time as both moves use the same button. The brothers are restricted to using the ball that matches their color.
- On the Punch Ball Mario Bros. title screen, a Punch Ball appears instead of the game's normal cursor.
- Punch Balls are Mario and Luigi's first projectile weapons.
- Story page of the instruction manual.