Pyoderma gangrenosum (PG) is a rare, but serious neutrophilic dermatosis characterized by recurrent painful cutaneous ulcerations. It is commonly associated with inflammatory bowel disease, rheumatoid arthritis, and hematological malignancies. Because laboratory evaluations and histologic features of PG are nonspecific, diagnosis is based on the clinical features of the ulcer and requires exclusion of other conditions that cause such ulceration. The disease responds to glucocorticoids, immunosuppressives, and anti-inflammatory drugs. We present a 30-year-old man with acute myelogenous leukemia (subtype M5) and bullous PG. Treatment with high-dose prednisolone was successful.