In this cooperative multicenter study for surgical repair of Achilles tendon rupture using a composite implant, 48 patients underwent 52 procedures. This implant is composed of filamentous uniaxially aligned carbon fibers coated with an absorbable polymer. This highly biocompatible implant acts as a scaffold for regrowth of collagenous tissue. The early strength of this repair is provided by the composite implant and by the rapid ingrowth and attachment of new tissue, which allows for an earlier and more vigorous rehabilitation program. Patients with a minimum follow-up of 1 year form the basis of this article. The overall average follow-up is 2.1 years. Three cohort groups were observed on a temporal basis and quantitatively evaluated at 1 year (N = 29), 18 months (N = 22), and 2 years (N = 20), respectively. These three groups demonstrated continuous improvement during the first postoperative year. A high level of function was maintained throughout the second year. Repair of chronic injuries (N = 15) was compared with repair of acute injuries (N = 12) at 1 year following surgery. Both groups greatly improved. However, the acute group had more serious preoperative deficits but improved to a slightly better overall level. Of the patients having at least 1 year follow-up, 86% had a good or excellent result. There was no increased morbidity associated with the use of the carbon implant.