Gastrophrynoides immaculatus has a long and pointy snout eye of diameter 2.6-3.0 times; dorsal and ventral smooth skin without any pattern; a large tubercle and oval metakarpa; evenly gray brown dorsal. Head slightly wider than length(HW / HL 1.06) and shaped like a triangle from the dorsal profile. Short medium hand, small discs, round and indented 'circum-marginal' fingertip. Non web fingers. Medium length hind legs. The maximum size for females is 29.3 mm long from nozzle to the anus. This species is only found at 800-1400 m altitude in Gunung Besar Hantu, Negeri Sembilan. The discovery of this species have been recorded during the Scientific Expedition of Forest Biological Diversity of Gunung Besar Hantu, Negeri Sembilan in 2010.