This study was carried out to investigate the flora of Is. Gageo (Jeollanam-do). The vascular plants were collected 13 times (from June 2008 to September 2011), and 465 taxa in total were identified, including 112 families, 301 genera, 402 species, 3 subspecies, 49 varieties, 9 forms and 2 hybrids. 171 taxa were first records for the region. Among them were seven taxa of Korean endemic plants and the Ministry of Environment-designated plants, which should be protected by the wildlife protection law, were identified as three taxa. There were 54 taxa of the flora with the levels III, IV, V in the floristic indicator plants which was designated by Ministry of Environment. The naturalized plants were identified as 29 taxa, and their naturalization ratio and urban index were found to be 6.2% and 9.0% respectively. There existed many kinds of plants resources having conservational value like $Loxogramme$ $salicifolia$, $Sarcandra$ $glabra$, $Osmanthus$ $insularis$, $Saussurea$ $polylepis$, $Carex$ $ligulata$ var. $austrokoreensis$, $Hosta$ $jonesii$, $Cyrtosia$ $septentrionalis$, etc., in this area. As therefore clear that appropriate plans to conserve the natural habitat of Is. Gageo must be made immediately.