The basement membrane matrix of skeletal muscle has a tubular configuration resembling that of peripheral nerves. Grafts made of autogenous skeletal muscle denatured by freezing and thawing were used to repair the ulnar nerve in marmosets. By six months, normal hand function had returned and the grafts were shown to transmit normal compound extracellular action potentials in both directions. Morphological examination of the grafts and distal nerves revealed normal axon numbers and axon maturity. Myelination in the graft was found to take place more slowly than in the distal nerve segment. It is suggested that such grafts might be of use in the repair of human peripheral nerves.