Ant fauna was investigated in the Peninsular Botanical Garden (Khao Chong), Southern Thailand by hand collecting, sifting and colony searching in 2000, 2001, 2003 and 2004. A total of 155 species belonging to 60 genera in twelve subfamilies is recorded here. Species-rich genera are Pheidole, Polyrhachis, Camponotus, Leptogenys, Pachycondyla, and Crematogaster. Rare genera are Sphinctomyrmex, Leptanilla and Eurhopalothrix. Ant fauna of this area is discussed, in comparison with those of other sites in Southeast Asia and some places in Thailand. Species composition in this area was similar to that in lowland rainforests of other sites, but remarkably different from that in montane forests.