Eighty-four previously treated adult patients with acute leukemia and malignant lymphoma were treated with (2″R)-4′-O-tetrahydropyranyladriamycin (THP). THP (10–55 mg/m2) was administered by i.v. bolus injection daily for acute leukemia, and according to three different schedules for malignant lymphoma: daily, weekly or once every 3–4 weeks. Complete and partial remission (CR and PR) were achieved by 1 (5%) and 3 of 19 patients with acute myelogenous leukemia and by 2 (13%) and 3 of 15 patients with acute lymphoblastic leukemia, respectively. All CRs were in the groups receiving 25 mg/m2 THP daily. CR and PR were achieved by 6 (14%) and 8 of 42 patients with non-Hodgkin lymphoma (NHL) and by 4 (50%) and 2 of 8 patients with Hodgkin's disease (HD), respectively. No particular sensitivity was found among the subtypes of NHL and HD. Response (CR+PR) was noted in 10 (40%) of 25 patients treated every 3–4 weeks, in 1 (17%) of 6 treated weekly, and in 9 (47%) of 19 treated daily. The major side effects were myelosuppression and gastrointestinal toxicities. Alopecia was observed in only 10 (12%) patients. ECG abnormalities were observed in 7 (10%) patients, all of whom had previously been treated with other anthracyclines. No severe cardiotoxicity was observed.