Forty-four black-tailed jackrabbits, Lepus californicus melanotis Mearns, 1890, were collected near Denver from August, 1972, through July, 1973, and examined for parasites. Recovered parasites and their infection rates were: Eimeria sp. 100%, Cittotaenia sp. 27%, coenuri of Multiceps sp. 57%, Cediopsylla inaequalis 14%, Hoplopsyllus affinis 9%, Haemodipsus setoni 2%, Dermacentor andersoni 14%, and Haemaphysalis leporis-palustris 25%.