The record for the most home runs in a single MLB season was set by Barry Bonds in 2001 when he hit 73 home runs. Bonds, playing for the San Francisco Giants, surpassed the previous record of 70 home runs set by Mark McGwire in 1998. This achievement is often cited in discussions about offensive records in baseball and remains one of the most celebrated and debated records in sports history, particularly within the context of steroid use and its impact on the game.