The aim this study is to establish the floristic composition of vascular plants of Mt. Gwangdeok. The survey was performed 12 times from May to November in 2007 and April to November in 2011. Vascular plants observed were 539 taxa containing 100 families, 317 genera, 467 species, 6 subspecies, 60 varieties and 6 formae. Among the investigated plants, 17 taxa (3.1%) were Korean endemic. The rare plants designated by the Korea Forestry Service in this region were 20 taxa. The floristically and geographically important plants were 90 taxa: grade I, II, III, IV, and V species were 29, 25, 21, 11, and 4 taxa, respectively. 32 taxa (9.9%) were found in this region and it is relevant to 5.9% of the total taxa number of this region.