A total of 589 serum specimens were collected from mule deer ( Odocoileus hemionus) (133) and wapiti (Cervus elaphus) (456) in eight national parks and/or adjacent lands in the western USA. Thirty two percent of the samples were collected from immobilized animals and 68% from hunter-killed animals in or near Glen Canyon National Recreation Area, Bryce Canyon National Park (NP), and Zion NP, Utah; Yosemite NP, California; Rocky Mountain NP, Colorado; Upper Yellowstone NP, Montana, and Grand Teton NP, Wyoming. Serum specimens were tested for the presence of antibodies against selected disease agents. Overall seroprevalences for mule deer were 77/133 (58%) for parainfluenza-3 virus (PI-3), 42/133 (32%) for bovine herpesvirus-1 (BHV-1), 79/133 (59%) for bovine virus diarrhea virus (BVD), 73/133 (55%) for respiratory syncytial virus (RSV), 14/133 (11%) for bluetongue virus (BT), 18/133 (14%) for epizootic hemorrhagic disease virus (EHD), 3/133 (2%) for Borrelia burgdorferi, and 1/133 (1%) for Francisella tularensis. None of the deer sera presented antibodies for Leptospira spp., Brucella abortus and Anaplasma marginale. For wapiti, overall prevalences were 262/456 (57%) for PI-3, 211/456 (46%) fdr BHV-1, 251/456 (55%) for BVD, 247/456 (54%) for RSV, 1/456 (< 1%) for BT, 16/456 (4%) for Leptospira pomona, 13/456 (3%) for Leptospira hardjo, and 8/456 (2%) for B. abortus. No antibody titers were detected for EHD, A. marginale, and other Leptospira serotypes. This survey documents seroprevalence of selected park cervid populations to domestic livestock pathogens. Further research on the epidemiology of these potential pathogens in wild ungulates in national parks is recommended.