This experiment was conducted to determine the influence of feed intake prior to heat exposure on thermoregulatory physiological responses of broilers. Eight broilers, which had received one of four levels of feed diet (O, 25,50 and 75 g) at 0900 at 22℃ before heat exposure, were subjected to exposure to 38℃ for 3hours from 1400 to 1700. Rectal temperature (Tr), leg shank skin temperature (Ts), respiration rate (RR) and heart rate (HR) increased with increase in feed intake level at 22℃ before heat exposure. During exposure to 38℃, no differences were observed in heat production (HP) between levels of feed given. There were also no differences in Tr, Ts, RR and HR. However, these physiological indices increased significantly (P<0.01) with duration of exposure to 38℃. HP increased with the increase in Tr. RR was at maximum when Tr was at about 42.5℃. These results may show that the effects of feed restriction prior to high temperature exposure on thermoregulatory physiological responses of broilers have disappeared within shorter time. Jpn. J. Livest. Management, 33(2) : 39-46. 1997. Received March 3,1997. Accepted July 22,1997.