To evaluate the efficacy of autologous bone marrow plasma injection after rotator cuff repair. Fifty six patients who were diagnosed with rotator cuff tear and had arthroscopic rotator cuff repair were selected. Twenty six patients had additional autologous iliac bone marrow plasma injection following arthroscopic rotator cuff repair and remaining 28 patients had repair procedure only. Aspirated iliac bone marrow was centrifuged at 1,800 rpm for 20 to 30 minutes before injection. Pain and function were evaluated using Constant Shoulder Score, University of California at Los Angeles Shoulder Scale, Oxford Shoulder Score and Visual Analogue Scale. Postoperative sonography was done to evaluate the condition of rotator cuff tendon. The group with autologous bone marrow plasma injection showed significantly better functional results. In songraphic examination, all rotator cuffs were healed successfully. Injection of autologous bone marrow plasma after rotator cuff repair may enhance biologic healing and thereby contribute to pain relief and functional improvement.