BACKGROUND After reinsertion on the humerus, the rotator cuff has limited ability to heal. Growth factor augmentation has been proposed to enhance healing in such procedure. OBJECTIVE This study was conducted to assess the efficacy and safety of growth factor augmentation during rotator cuff repair. METHODS Randomized controlled trial; Level of evidence, 1. METHODS Eighty-eight patients with a rotator cuff tear were randomly assigned by a computer-generated sequence to receive arthroscopic rotator cuff repair without (n = 45) or with (n = 43) augmentation with autologous platelet-rich fibrin matrix (PRFM). The primary end point was the postoperative difference in the Constant score between the 2 groups. The secondary end point was the integrity of the repaired rotator cuff, as evaluated by magnetic resonance imaging. Analysis was on an intention-to-treat basis. RESULTS All the patients completed follow-up at 16 months. There was no statistically significant difference in total Constant score when comparing the results of arthroscopic repair of the 2 groups (95% confidence interval, -3.43 to 3.9) (P = .44). There was no statistically significant difference in magnetic resonance imaging tendon score when comparing arthroscopic repair with or without PRFM (P = .07). CONCLUSIONS Our study does not support the use of autologous PRFM for augmentation of a double-row repair of a small or medium rotator cuff tear to improve the healing of the rotator cuff. Our results are applicable to small and medium rotator cuff tears; it is possible that PRFM may be beneficial for large and massive rotator cuff tears. Also, given the heterogeneity of PRFM preparation products available on the market, it is possible that other preparations may be more effective.