Vegetation sampling and sticky trapping were conducted to investigate overwintering thrips species and their vernal activities, respectively, in winter-spring seasons on Jeju island, Korea, from 1994 to 1996. In addition to Thrips palmi Karny, which was reported overwintering on Jeju island by Lee et al. (2001), twelve thrips species belonging to the family Thripidae were found on vegetation during the winter season. Among them, eight species including economically important thrips, Frankliniella intonsa(Trybom), F. occidentalis (Pergande), and T. tabaci Lindeman were found to overwinter on vegetation in the island. Scitothrips dorsalis Hood, however, is uncertatin whether or not it can overwinter on vegetation. Vernal activities of thrips observed by sticky trapping were different among species. All thrips, except for T. palmi, were caught after mid April, and F. intonsa and S. dorsalis were earlier than F. occidentalis and T. tabaci.