The purpose of this study was to examine the effects of a 4-month season of collegiate tennis on glenohumeral joint internal and external rotation strength and range of motion in female collegiate tennis players. Eleven female collegiate tennis players were isokinetically tested to assess glenohumeral joint internal and external rotation strength with 90 degrees of abduction on a Cybex 6000 isokinetic dynamometer. Subjects were also measured for internal and external rotation range of motion using a universal goniometer with 90 degrees of abduction. Measurements were taken before and immediately after a 4-month season of competitive collegiate tennis play. A repeated-measures analysis of variance showed no significant difference in internal or external rotation strength or range of motion between pre- and postseason measures. Results from this study show that, despite 4 months of competitive tennis play, changes in rotational strength and range of motion did not occur. These data have implications for clinicians as well as strength and conditioning professionals designing rehabilitation and preventative conditioning programs for athletes in this population.