If you mean by an individual player, the answer is Barry Bonds: 73 home runs in 2001. The American League record is still owned by Roger Maris, who hit 61 home runs in 1961.
If you mean by a team, that record was set by the Seattle Mariners in 1997 with 264 home runs.
If you mean the highest single-season major league total, the most home runs hit in the major leagues in a single season occurred in 2000, with 5,693.
Hank Aaron had the most home runs for a regular season.
In MLB history, the player who hit the second most home runs in a season was Mark McGwire who hit 70 in 1998.
The most home runs Hank Aaron hit in an MLB season was 47 in 1971.
Barry Bonds has the most homeruns in a single season. His record is 73.
In MLB, Eddie Murray with 504 ... the most HRs he hit in a season was 33 in 1983.
Hank Aaron had the most home runs for a regular season.
hank aaron
In MLB history, the player who hit the second most home runs in a season was Mark McGwire who hit 70 in 1998.
The most home runs Hank Aaron hit in an MLB season was 47 in 1971.
Barry Bonds has the most homeruns in a single season. His record is 73.
Phillies
In MLB, Eddie Murray with 504 ... the most HRs he hit in a season was 33 in 1983.
In MLB, 0.The most home runs Aaron hit in a season in MLB was 47 in 1971.
The record is still held by Barry Bonds.
1997 Seattle Mariners
Through the 2013 season, Alex Rodriguez hit the fifth most home runs, with 654.
Albert Pujols lead Major League Baseball with 47 Home Runs in 2009