Context: Imbalanced shoulder muscles might cause poor posture in swimmers, which has been implicated as potential cause of injury. Objective: To determine whether a training program can reduce forward shoulder posture. Design: Prospective pseudorandomized. Setting: College swimming pool. Participants: 39 competitive swimmers (age 16 ± 2 years) divided into an exercise group (n = 24) and a control group (n = 15). Intervention: The experimental group performed a partner-stretching program on the anterior shoulder muscles and a strengthening regimen focusing on the posterior shoulder muscles for 6 weeks. The control group participated in normal swim-training activities. Main Outcome Measures: Shoulder posture was measured as the distance from the anterior acromion to a wall using a double-square method. Results: The experimental group significantly reduced the distance of the acromion from the wall in a resting posture (–9.6 ± 7.3 mm) as compared with the control group (–2.0 ± 6.9 mm). Conclusions: A training routine might reduce the forward shoulder posture present in most competitive swimmers.