Purpose: To determine if the short-term impairment of sensory function in rat skin grafts known to be caused by antibody to nerve growth factor (anti-NGF) is a transitory effect or is long-lasting. Materials and Methods: Skin grafts measuring 1 cm² were harvested full-thickness from the dorsal region, one per animal, of male Sprague-Dawley rats. The grafts were rotated 180 degrees, sutured back onto donor site fascia and dressed. On postoperative day 6, the grafts were inspected for evidence of infection or necrosis. Test groups of ten animals each were given daily subcutaneous injections for 20 days of either anti-NGF (0.5 ml) or its control, pre-immune serum (P-serum) (0.5 ml). NGF (50 µ gr) and its control, cytochrome C (CyC 50 µ gr) were also administered to additional groups. Four months postoperatively, the grafts were assessed for pinprick sensation with the use of a hand-held device designed to deliver a constant force stimulus. A positive sensory response was observed as a twitch of the rat's back, a very characteristic and well-described reflex, involving the panniculus carnosus muscle. The stimulus was applied to each of 25 sectors of each graft and a positive response or the lack of a response noted by a blinded observer. A percentage of the graft responding positively was then calculated for each graft and then a mean percentage calculated for each group. Normal skin around the grafts was tested as a positive control. Results: Graft problems were noted in 2 animals in the anti-NGF group, 3 in the P-serum group, 4 in the NGF group and 3 in the Cyc group, resulting in their elimination. Four months postoperatively the mean percentage of grafts responding to stimulus ± STD were: Anti-NGF, 60%±18; control (P-serum), 87%±13; NGF, 82%±15; control (CyC), 83%±12. t-test analysis showed the anti-NGF group to be different from its control (p=0.005). NGF was not different from control. Conclusion: Short-term delivery of anti-NGF causes a long-term decrease in sensory function in rat skin grafts indicating that endogenous NGF plays a role in the process of graft reinnervation. Exogenously-administered NGF does not affect pinprick sensation in this model.