We described a case of systemic infection by Coccidioides sp. in a dog. An adult, mixed breed, free-ranging male dog presented with clinical signs that included apathy, cachexia, anorexia, limited mobility with sternal recumbency, bilateral mucopurulent ocular discharge, dyspnoea, pulmonary crepitation, erosive and nodular lesions on the skin, and swelling and stiffness of the left tibiotarsal joint. The dog was submitted to a postmortem examination. Grossly, there were multiple yellow to white nodules in various organs. Histologically, the lesions were characterized as pyogranulomatous inflammation associated with fungal spherules morphologically consistent with Coccidioides sp. The dog was concomitantly diagnosed with undifferentiated sarcoma affecting the skin, lymph nodes, liver, and testicles. The diagnosis of coccidioidomycosis was made based on the histologic changes associated with morphotintorial features and positive immunolabeling of organisms with anti-Coccidioides immunohistochemistry. This case demonstrated that Coccidioides sp. can infect dogs that inhabit urban centers in the semiarid region of Northeastern Brazil, likely due to exposure to dust from contaminated environments.