The study deals primarily with the documentation of species diversity of bats along the elevational gradient of Upper Balogo, Anick and Mount Aguir-Aguir, Pigcawayan, Cotabato, Mindanao. The diversity and dominance per elevation site and relative density of bat species are determined. The study is conducted from August 2000 to April 2001. The identified species are Cynopterus brachyotis, Macroglossus minimum, Ptenocherius jagon, Rousettus amplexicaudatus and Scotophitus leuhlii. Among the bats identified, Ptenocherius jagon is known to exist only in the Philippines. Cynpterus brachyotis has the highest relative density while Macroglossus minimum has the lowest relative density.