Urban and agricultural land use may increase the risk of disease transmission among wildlife, domestic animals, and humans as we share ever-shrinking and fragmented habitat. American badgers (Taxidae taxus), a species of special concern in California, USA, live in proximity to urban development and often share habitat with livestock and small peridomestic mammals. As such, they may be susceptible to pathogens commonly transmitted at this interface and to anticoagulant rodenticides used to control nuisance wildlife on agricultural lands. We evaluated free-ranging badgers in California for exposure to pathogens and anticoagulant rodenticides that pose a risk to wildlife, domestic animals, or public health. We found serologic evidence of badger exposure to Francisella tularensis, Toxoplasma gondii, Anaplasma phagocytophilum, canine distemper virus, and three Bartonella species: B. henselae, B. clarridgeiae, and B. vinsonii subsp. berkhoffii. Badger tissues contained anticoagulant rodenticides brodifacoum and bromadiolone, commonly used to control periurban rodent pests. These data provide a preliminary investigation of pathogen and toxicant exposure in the wild badger population.