Mast cell tumors (or mastocytomas) are common, benign skin tumors in ferrets. Although they are not life-threatening, they can cause pruritus, bleeding, pain, and scab formation. Prior treatment recommendations have been surgical excision, which requires general anesthesia or sedation. This lecture will discuss the treatment protocol, outcome, and side effects of intralesional triamcinolone administration in ferrets with mast cell tumors. All mast cell tumors were diagnosed via fine-needle aspiration before injection with triamcinolone. This offers a safe, inexpensive, and highly effective treatment of mast cell tumors in ferrets.