Shoulder kinesthesia has not been extensively studied in upper extremity athletes. The purpose of this study was to determine if there were differences in threshold to detection of passive motion between dominant and nondominant shoulders of healthy overhead athletes in two positions, 0 degrees and 75 degrees of external rotation. In addition, the study attempted to determine if there was a relationship between the range of external rotation (ER) and internal rotation (IR) and the threshold to detection of passive motion values. Shoulder kinesthesia was assessed in the dominant and nondominant shoulders of 20 collegiate athletes participating in unilateral upper extremity sports. A proprioceptive testing device passively moved the shoulder into internal and external rotation. The dominant shoulder had a significantly greater difficulty detecting motion compared with the nondominant arm at both 0 degrees and 75 degrees of external rotation. Both shoulders exhibited enhanced kinesthesia (lower threshold to detection of passive motion scores) at 75 degrees of external rotation compared with 0 degrees, where the glenohumeral joint capsule is relatively taut. The results of this study suggest that healthy upper extremity athletes may have kinesthetic deficits in their throwing shoulder compared with their nondominant shoulder.