This study examined the freezing behaviors in rats with dorsal hippocampal lesions in pavlovian aversive conditioning situation using electric shock as US. Data were obtained by behavioral observations in blocks of 5 sec period in total experimental session. Results showed tbat the hippocampectomized rats exhibited the significant reduction in the number of freezind behaviors duting both CS and ITI compared to both operated control and intact group. From observational data,lesions neither affected the sensitivity to shock nor the CS-US association learning. Thus, this study supported the bypothesis that hippocampus might mediate internal response inhibition and/or movlng arrest.