Introduction: Several surgical techniques for arthroscopic repair of the rotator cuff have been described in the literature. The aim of this study was to determine whether the suture thread locking method in double-row anchors influences their biomechanical properties. We compared the pullout strength of two anchors with different locking mechanisms. Introduction: Several surgical techniques for arthroscopic repair of the rotator cuff have been described in the literature. The aim of this study was to determine whether the suture thread locking method in double-row anchors influences their biomechanical properties. We compared the pullout strength of two anchors with different locking mechanisms. Methods: We performed 30 pullout tests at 135° using two different double-row anchors, an interference fit lock (5.5 mm SwiveLock) and a combination lock (5.5 mm MultiFix S). One anchor of each type was implanted on the tuberosity of a bovine humeral bone. Results: Mean pullout strength was 239.29 ± 83.73 N for the SwiveLock anchors and 253.82 ± 87.65 N for the MultiFIX S anchors, mean displacement (in millimeters) was 28 ± 9 and 30 ± 12, respectively which were not statistically significantly different. Conclusion: The addition of an internal lock in the double-row suture-locking anchor did not improve the biomechanical properties in a pullout test of 135°