A female North American porcupine (Erethizon dorsatum) was evaluated for a unilateral pedal crusting and alopecic dermatopathy. Fungal culture and histopathology testing revealed Microsporum gypseum dermatophytosis. Treatment with topical miconazole was initiated and then discontinued after 9 days and changed to oral terbinafine. Twenty-eight days after initial examination, clinical signs were improving, and fungal cultures of the front foot, muzzle, and noninfected area along the dorsum were negative for M. gypseum. Visual exams were conducted on a regular basis. Eighty-three days after initial evaluation, clinical signs had completely resolved and repeat fungal cultures were negative. One of the animal's keepers was suspected to have acquired a dermal fungal infection 3 days after contact with this porcupine, and lesions had resolved after treatment with topical ketoconazole. To the authors' knowledge, this is the first report of M. gypseum diagnosed and treated in a captive North American porcupine. Veterinary staff and zookeepers should be aware of this potentially zoonotic infection.