A group of 49 patients with advanced non-Hodgkin's lymphoma were entered in a combination-chemotherapy protocol (cyclophosphamide L2). Of 14 patients with diffuse poorly differentiated lymphocytic lymphoma (DPDL), 64% responded with two partial remissions (PR) and seven complete remissions (CR). Both PRs are stable at 17+ months while six of the CR group are free of disease at 3+-23+ months. Fifty-three percent of 30 patients with diffuse histiocyctic lymphoma (DHL) responded with 23% attaining CR status. Of the nine PR patients, six are stable at 11+-23+ months while six of the seven CR group are without disease at 9+-27+ months. The major toxic effect was bone marrow suppression with two deaths during periods of neutropenia; one of these deaths was definitely drug related. The encouraging results in the DPDL category have led to a continuation of this protocol for patients with this histologic type. In patients with DHL other approaches are being explored.