Twenty-six pronghorn antelope (Antilocapra americana) were collected in an area of eastern Montana where bovine anaplasmosis is enzootic. Their sera were examined for evidence of anaplasmosis by the complement-fixation test. Strong false positive reactions (3 and 4 reactors) occurred for 19 of the sera tested; 6 sera were anticomplementary. Inoculation of antelope blood into anaplasmosis-free intact calves did not produce clinical or serological evidence of anaplasmosis, and anaplasma bodies were not found in stained blood smears of antelope or recipient calves.