Purpose of this study is to describe the treatment, surgery, rehabilitation and return to daily life subject pectoralis major muscle rupture. The in patient with was a 26 years old, injured in training due to hyperextension and external rotation. Physical examination, manual test, and MRI were used to diagnose pectoral muscle rupture and operation took for the pectoralis major muscle rupture with allograft. The subject was referred for rehabilitation from 3 weeks. Range of motion (ROM) exercise was mainly performed until 3 months, strength was performed with tubing band, body weight, machine training and proprioceptive exercise. Shoulder range of motion (external rotation, flexion) were measured with goniometer and muscle strength (flexion, adduction, internal rotation) were measured with dynamometer. At 6momths, external rotation ROM was 50° (unaffected side 60°), and flexion almost recovered at 3 months. Muscle strength was gradually increased to 6.2kg, 15.7kg, and 27.0kg in flexion, while internal rotation The pain remained slightly after 9 months. The present results suggest that ROM exercise and strengthening exercise increase the muscle power and ROM, and decrease the pain.