47 in 1971.
The most home runs Hank Aaron hit in one season was 47, in 1971.
It changes
Jim Thome retired after the 2012 season with 612 career home runs, the seventh-highest total in the history of major league baseball.
That was 46 home runs and 95 RBIs by Alfonso Soriano in 2006 for the Washington Nationals. Second highest was 45 home runs and 96 RBIs by Harmon Killebrew for the 1963 Minnesota Twins.
in 2001 barry bonds hit 73 home-runs beating mark mcgwire's record of 70 (done in 1998 by mark)
Roger Maris hit 61 home runs in the 1961 season.
In 2006, the Yankees hit 210 regular season home runs. They also hit 4 more in the postseason.
Dave Klingman holds the record for most home runs hit during a retirement season. He hit 35 home runs in his 1987 final season.
The Toronto Blue Jays hit the most home runs in 2010 hitting 257 which was 46 more than the next highest team ( Boston Red Socks- 211).
Mark McGwire had over 70 home runs in one season
No ... the most home runs Cobb hit in a season was 12 in 1921 and 1925.