A variety of trimethyltin (TMT) -produced sensory and behavioral dysfunctions have been reported. In this study the functional integrity of the somatosensory system was evaluated. Animals were tested using three different measures prior to (day 0) and 1,4, and 16 days following dosing with either 0 (saline) or 7 mg/kg TMT. The tests employed were: (1) hotplate pain threshold; (2) dorsal caudal nerve response threshold and conduction velocity; and (3) the somatosensory evoked response (SER). In the hot-plate test, TMT treated animals took longer to lick the hind paws in response to the heat. No effects were seen in the nerve function evaluation (conduction velocity and threshold), although increased N1, P1, and P2 latencies and decreased N1P1 amplitude were seen in SER recordings. The fact that no peripheral nerve function effects were observed suggests that the hot-plate and SER findings were the result of central nervous system dysfunction.