Previous studies have indicated that acute exposure to triethyltin (TET) increases latencies of the flash evoked response (VER) recorded from the rat cortex. TET also produces hypothermia, which may be modified by altering environmental (ambient) temperature. In this study, the role of ambient temperature in determining the effects of acute TET upon the VER was examined. Rats with chronically implanted electrodes were administered either TET (6mg/kg) or saline, and maintained in either a warm (30C) or cool (22C) environment for the next 7 hrs. VERs were recorded during this 7 hr period, and at regular intervals for the next 2 weeks. TET increased VER peak latencies. VER peak latencies recorded from animals exposed to TET in a warm room remained elevated for a longer period of time, thus indicating a more severe impact of the TET exposure. This study indicates that toxicant induced alterations in core temperature are potential determinants of other toxicant-induced effects.