Fulminant necrotizing soft-tissue infection of the external genitalia and perineum (Fournier's gangrene) occurred in a patient with severe alcoholic hepatitis. By means of radical débridement and disinfection of the necrotizing tissue, use of broad-spectrum antibiotics and prednisolone, and other supportive measures, Fournier's gangrene and severe alcoholic hepatitis eventually subsided with broad skin defects in the waist and external genitalia. Later, the skin defects were successfully reconstructed with skin grafts. Although the route of bacterial intrusion could not be defined, Fournier's gangrene presumably developed in a background of impaired immunological defences, principally associated with habitual massive alcohol consumption and profound liver dysfunction. This present case highlights not only the underlying immunocompromised condition but also the need for concern regarding the urogenital and anorectal areas as potential foci of life-threatening infection in patients with liver dysfunction, especially when related to alcohol intake.