Tendon repairs done with strong suture materials fail by suture pull out. To avoid pull out, suture loop needs to have a strong grip on the tendon. The aim of this study was to determine whether a single suture loop has a better grip of the tendon when multifilament or flat sutures are used compared with a conventional monofilament round suture. A cross-locking or simple grasping suture loop was placed into the distal end of a human cadaveric tendon using nitinol wire sutures in the following configurations: round monofilament (200 µm), round multifilament (4 × 100 µm), and flat multifilament (4 × 30 µm × 445 µm). The mean pull-out strength of the round multifilament (49.4 N) and flat multifilament sutures (50.7 N) were significantly higher than that of the round monofilament nitinol suture (36.5 N) when a locking loop was used. Suture grip can be improved by using a multifilament suture and a locking type of suture configuration.