Anesthetics and body temperature alterations are both known to alter parameters of sensory-evoked responses. However few studies have quantitatively assessed the contributions of hypothermia to anesthetic-induced changes. Two experiments were performed. In the first, chronically implanted rats were injected with either 0, 0.05, 0.10 or 0.20 ml Chloropent/100 gb.w, while body temperature was maintained. Flash evoked potentials recorded 30 min later showed increased latencies but only minor (not statistically significant) changes in amplitude. In the second experiment the same rats were anesthetized with 0.35 ml Chloropent/100 g b.w. and rectal temperature was systematically varied between 31C and 37C.