A collection of 358 fleas representing 6 families, 19 genera, and 21 species was made from eight species of mammals in seven provinces within Ancash Department, Peru. Specimens were also obtained from bank cavities and water flea traps. A new species of flea. Ectinorus, alejoi (Rhopalopsyllidae) collected from Lagidium peruana Meyen, 1833 (vizcacha) is described from Recuay Province, bringing the total number of species belonging to the genus Ectinorus to 32. The male of Plocopsylla pallas (Rothschild, 1914) (Stephanocircidae) is also described for the first time. Plocopsylla pallas (16%), Neotyphloceras crassispina hemisus Rothschild, 1914 (14%). and Cleopsylla townsendi Jordan, 1936 (9%) comprised 39% of the total number of fleas collected. Three fleas are reported from Peru for the first time (D. stejnegeri. P. achilles, and E. alejoi). Eleven additional species represent new records for Ancash Department (A. thurmani, C. townsendi, C. m. minerva, E. gallinacea, E. claviger, N. c. hemisus, P. pallas, P. d. quitanus, S. inca, T. bleptus, and T. titschacki).