In briefPerformance characteristics of professional athletes are of interest to those involved in sports. Major league baseball players were tested for muscular strength, cardiovascular endurance, and body composition. Comparisons were made among positions and with other professional athletes. Results indicated that differences in strength and body composition existed among positions. Cardiovascular endurance of baseball players was comparable to that reported for other professional athletes. These data may be useful as a point of reference for coaching, testing, training, and selecting athletes.