The purpose of this study was to evaluate the outcome of subcoracoid pectoralis major transfer for the treatment of irreparable anterosuperior rotator cuff tears. This type of tear involves complete rupture of the subscapularis in combination with either the supraspinatus alone or the supraspinatus and infraspinatus. These ruptures are characterised by a poor quality of the rotator cuff that does not allow for a direct tendon-to-bone reconstruction. Between 2000 and 2006, 15 patients were treated using a deltopectoral approach and transfer of the clavicular part of the pectoralis major to the lesser tuberosity and to the anterior part of the greater tuberosity. After an average follow-up (follow-up rate 100%) of 37 months the average functional rating using the Constant and Murley score (CS) increased from 51.73 +/- 16.18 to 68.17 +/- 8.84 points (p = 0.005). The mean subcategories of the Constant score for pain (p = 0.005), activities of daily living (p = 0.008) but not for range of motion (p = 0.9), significantly improved. At follow-up 13 patients (87%) were available for magnetic resonance imaging (MRI) of the shoulder. Nine patients (70%) had an intact transferred pectoralis major muscle, two (15%) had one that was thin but intact and two patients a rupture (one complete). Two patients had postoperative haematoma and one patient developed cuff tear arthropathy. The good results confirm that pectoralis major transfer is a reliable treatment option for irreparable anterosuperior rotator cuff injuries with significant improvement in pain and function.