Twenty-five palmaris longus muscles were transplanted into the forearm (orthotopic autografts) or into the face (heterotopic autografts) in 15 Rhesus monkeys. These muscles were transplanted with or without anastomosis to a motor nerve. No significant difference was observed long-term between the grafts done with or without prior denervation of the muscle. The forearm muscle grafts without neurorrhaphies formed a static, fibrous sling which did not contract. The forearm autografts with neurorrhaphy and the grafts to the face, with or without neurorrhaphy, all developed regenerating skeletal muscle fibers and showed contractile activity.