Records from 653 patients treated between 1991 and 1998 in the Oncology Practice Patterns Study (OPPS) were analyzed to determine contemporary chemotherapy delivery patterns in patients with intermediate-grade non-Hodgkin's lymphoma (NHL). Of the 653 patient records reviewed, 90 (14%) omitted an anthracycline or mitoxantrone (Novantrone) from primary therapy. Among patients receiving CHOP (cyclophosphamide [Cytoxan, Neosar], doxorubicin HCl, vincristine [Oncovin], prednisone) or CNOP (cyclophosphamide, mitoxantrone, vincristine, prednisone), 134 (27%) of 492 received an average relative dose intensity of less than 80% of the literature-referenced dose, due either to an inadequate planned or delivered dose. Of 181 advanced-stage patients with responsive disease, 28 (15%) failed to receive at least six treatment cycles. Overall, 283 (43%) of 653 patients potentially received suboptimal chemotherapy due either to choice of regimen or chemotherapy delivered. Patient age > or = 65 years and cardiac comorbidity appeared to have the greatest influence on a physician's decision regarding chemotherapy administration. Among the 492 patients who received CHOP or CNOP, 235 (48%) experienced a delay or reduction in chemotherapy dose (usually neutropenia-related), 100 (20%) developed mucositis, and 116 (24%) were hospitalized for febrile neutropenia. Growth factor was administered to 261 patients (53%), and its primary prophylactic use was associated with a significant reduction in the incidence of hospitalizations for febrile neutropenia in all patient subgroups receiving appropriate chemotherapeutic dose intensity (P = .02). This assessment of chemotherapy delivery to patients with intermediate-grade NHL showed significant variation from current standards. Further analysis of factors influencing chemotherapy delivery might improve therapeutic outcomes.