In brief: One hundred and thirty-seven major league baseball players and 32 coaches were tested for body composition, and comparisons were made among positions and among teams. Shortstops were the leanest players (9.2% fat), outfielders averaged 9.9%, and pitchers were the fattest (14.7% fat). The players' body composition reflected the movement patterns and defensive requirements of their positions. There were few differences among teams, and in general, the baseball players were comparable to other professional athletes.