Due to the forensic importance of Dermestes, which allows to determine death times or post mortem interval and the lack of knowledge of this subfamily in a dry forest, this contribution is presented to provide the first records of Dermestes in the province of Castilla, in Piura, northern Peru. The material used was collected over the year 2017, in carcasses of giunea pigs in states of active decomposition, advanced and dry remains; 3 species were registered: Dermestes ater, D. frischii and D. maculatus, of which an illustrated key is included to differentiate them one from another.