Seventeen patients with malignant lymphoma were entered into a phase II study of peplomycin (PEP) to determine the efficacy of the drug. There were 8 males and 9 females with a median age of 64 yrs (range 3-74 yrs) and a median PS 3 (range 2-4). Three of these were children. At first PEP was given intermittently and intramuscularly (8 cases) at a dose of 10 mg every one (3 cases) or two (5 cases) weeks, and then intravenously by 22-hr continuous infusion (9 cases) at a dose of 5 mg per day for 5 days. Mean cumulative dose was 78 mg. Objective responses were obtained in 6 patient (35%). CR lasting 4 weeks was obtained in one patient with diffuse mixed-type lymphoma. Five patients, one with diffuse medium-sized cell type and 3 with diffuse large cell type, had PR, lasting 6, 7, 7, 9, and 50+ weeks, respectively. Pulmonary fibrosis was found in two patients on autopsy and interstitial pneumonia in two patients clinically. Temporary high fever occurred in 7 patients, stomatitis in 3 patients and anorexia in 3 patients.