Thirty-seven patients with refractory lymphoma or cutaneous T-cell lymphoma were treated with 2'-deoxycoformycin (pentostatin; dCF), 5 mg/m2 intravenous (IV) bolus for 3 consecutive days of every 3-week cycle in this Eastern Cooperative Oncology Group (ECOG) trial. Included were 25 with the diagnosis of non-Hodgkin's lymphoma, three with Hodgkin's disease, eight with cutaneous T-cell lymphoma (CTCL), and one with unknown subtype, of whom 31 were considered eligible. The majority had failed at least two, but no more, conventional chemotherapy regimens. Ten (32%) of the eligible patients had a partial response (PR), including patients with nodular poorly differentiated lymphocytic (NPDL), nodular mixed (NM), diffuse poorly differentiated lymphocytic (DPDL), or diffuse histiocytic (DH), lymphoma mixed-cellularity (MC), Hodgkin's disease, and unknown subtype, and in four patients with CTCL. The overall median time to treatment failure (TTF) was only 1.3 months, but the range extended to 57.3 months. The overall response duration was 16.0 months, and the range extended to 53.4 months. Overall median survival was 2.7 months, with the range extending to 63.2 months. The majority of patients had no toxicity, but there were some instances of severe or life-threatening events. Four fatal toxicities occurred, in two patients with underlying pulmonary conditions and two with prior cardiac histories. From this study, we conclude that dCF is active in refractory lymphomas and CTCLs, should be avoided in patients with a history of serious pulmonary or cardiac diseases, and warrants consideration for incorporation of a low-dosage schedule into conventional combination chemotherapy regimens, including its use with biologic response modifiers.