Frostius pernambucensis, or the Frost's toad, is a species of toad in the family Bufonidae. It is endemic to the eastern Brazil where it is known from the Paraíba, Pernambuco, Alagoas, and eastern Bahia states.
Calling adult males from Santa Teresinha, Bahia had an average snout–vent length of 27.8 and 36.8 mm (1.09 and 1.45 in) in 2008 and 2009, respectively. The tympanum is small and vertically elliptical. The digits are long, laterally expanded, and have developed discs. Coloration of both dorsal and ventral surfaces is brown to light brown. The iris is yellow.
The male advertisement call is a long, pulsed call, lasting about eight seconds and having pulse rate of seven per second. The call is repeated about twice every minute.