The bioabsorbable poly-l/d-lactide (PLDLA) 96/4 suture has good biomechanical and knot properties, and sufficient tensile strength half-life for flexor tendon repair. In the present study, the biocompatibility of PLDLA suture was compared with that of coated braided polyester suture in the rabbit flexor digitorum profundus tendon repaired within the tendon sheath. Postoperative unrestricted active mobilization was allowed. The tendons were studied histologically after 1-, 3-, 6-, 12-, 26-, and 52-week follow-ups. No differences were found in the biocompatibility between the suture materials, with only scattered multinuclear giant cells near the sutures in both groups from 6 weeks onwards. At 52 weeks, most of the PLDLA material was absorbed and the histological structure of the tendon appeared normal, whereas in the polyester repairs the suture knots filled the repair site, causing bulking of the tendon surface, and the collagen alignment appeared disoriented. The results suggest that the PLDLA 96/4 is a suitable suture material for flexor tendon repair.