The authors present an experimental study of 30 rats, in which human dura mater preserved in glycerin was used to repair gaps in the Achilles tendon. The animals were killed 8 weeks after the surgery and evaluated by gross and microscopic examination. The results showed that the dura mater did not cause foreign-body reactions or adhesions and was surrounded by concentric layers of fibroblasts and collagen fibers, suggesting that it could be employed as a substitute for damaged tendons.