Mark David McGwire, nicknamed "Big Mac", is an American former professional baseball player currently serving as hitting coach for the Los Angeles Dodgers. As a first baseman, McGwire played in Major League Baseball for the Oakland Athletics and the St. Louis Cardinals between 1986 and 2001.
For his career, McGwire averaged a home run once every 10.61 at bats, the best at bats per home run ratio in baseball history. In 1987, he broke the single-season home run record for rookies, with 49. In 1998, McGwire and Sammy Sosa achieved national fame for their home run-hitting prowess in pursuit of Roger Maris' single season home run record; McGwire broke the record and hit 70 home runs that year. Barry Bonds now holds the record, after hitting 73 home runs during the 2001 season. In 2010, McGwire publicly admitted to using performance-enhancing drugs during a large portion of his career.