Malignant pyoperma is a rare, chronic, progressive, destructive ulcerating skin disease of unknown cause that affects the head and neck region of young adults. The disease is progressive but responds to high doses of systemically administered steroids. We present a case of malignant pyoderma developed on the left retroauricular area in 67 year-old male. The patient died of rapidly progressive, desructive, 15cm x 20 cm sized, phagedenic ulcer on the left retroauricular and neck area despite of various extensive local and systemic treatment. Histopathologic findings of tissue from the edge of the ulcer were non-specific, showing upper dermal necrosis and mixed inflammatory cell infiltrate in the deep dermis.