Ninety-two courses of daily low-dose intravenous nitrogen mustard were administered to 46 patients with advanced cutaneous lymphomas (mycosis fungoides, Sezary syndrome and lymphoma cutis). Seventy-eight % of patients showed objective clinical remission, and 35% reached a clinically disease-free state following 1 or more courses. The response rate was greater in patients with the plaque-tumor type of mycosis fungoides than in those with erythrodermic variants. Therapy was free of significant side effects.