Sera from 104 adult and 42 fawn pronghorn antelope (Antilocapra americana) from southeastern Idaho were tested against selected livestock pathogens. The numbers positive/numbers tested (% positive) were as follows: bovine virus diarrhea - adults 2/102 (2), fawns 0/41 (0);; infectious bovine rhinotracheitis - adults 27/101 (27), fawns 9/42 (22); parainfluenza 3 - adults 79/104 (76), fawns 22/42 (52); bovine adenovirus 7 - adults 42/103 (41), fawns 20/48 (48); bovine adenovirus 3 - adults 11/32 (34), fawns 4/14 (23); Anaplasma marginale - adults 1/104 (1), fawns 1/42 (2). There were no reactors to brucellosis, bluetongue, or epizootic hemorrhagic disease; The prevalence of reactors varied considerably for different locations and for different years.