A visual prepulse was applied just before a burst of white noise with various lead intervals ranging from 50 to 400 ms in hamsters. After habituation each hamster received 120 trials of the auditory noise with or without the prepulse. Amplitude of startle response increased significantly at 100 ms and 200 ms (n=10). This enhancement disappeared in blind controls (n=6). The amplitude of startle response decreased during exploratory behavior, grooming, sniffing or other movements. However, the facilitatory effects of the visual prepulse were consistent, regardless of the animal's behavioral states, except sniffing. The authors conclude that visual prepulse task is useful for studying the ability to detect visual signals in hamsters, and that further study is necessary to elucidate the factors affecting the enhancement of startle response in hamsters.