Prevalence of antibodies against canine parvovirus (CPV), canine distemper virus (CDV), and canine adenovirus type 1 (CAV) were determined among 152 coyotes (Canis latrans) at the Naval Petroleum Reserves (NPRC; California, USA) from 1985 to 1990. Overall prevalence of antibodies to CPV, CDV, and CAV was 66%, 37%, and 68%, respectively Prevalence of CPV and CDV varied significantly among years. Antibody prevalence did not differ between sexes for any disease, but did vary significantly among age classes and was lowest for pups (<1-yr-old). Among pups, antibody prevalence increased with age for all three diseases. Coyotes are a potential source of viral exposure for endangered San Joaquin kit foxes (Vulpes macrotis mutica), but variation in coyote abundance did not appear to influence antibody prevalence among kit foxes.