Fournier's syndrome is the fulminant necrotizing fasciitis of the external genitalia. The occurrence of Fournier's syndrome in patients with hematologic malignancies has been reported. Here we report a case of an intravascular lymphoma complicated with Fournier's syndrome due to multidrug-resistant Pseudomonas aeruginosa (MDRP). A 71-year-old Japanese man received intensive chemotherapy for recurring intravascular lymphoma. Blood culture revealed MDRP, and physical examination led to the diagnosis of Fournier's syndrome. Aggressive treatment that comprised granulocyte transfusion, granulocyte stimulating factor, endotoxin filtration, appropriate antibiotic coverage, and aggressive surgical therapy was administered, and this lead to the successful recovery from sepsis and Fournier's syndrome.