The safety and efficacy of compressed-cycle (14-day) standard-dose CHOP (cyclophosphamide/doxorubicin/vincristine/prednisone) supported with prophylactic recombinant granulocyte colony-stimulating factor (G-CSF; filgrastim) were evaluated in patients with aggressive non-Hodgkin's lymphoma (NHL). Patients with intermediate- or high-grade NHL (Working Formulation groups D-H and J; N = 120), accrued from 25 clinical practices, were given 6 cycles of standard-dose CHOP every 14 days. Granulocyte colony-stimulating factor 5 microg/kg was given daily subcutaneously in each cycle, starting on day 2 and continuing until the absolute neutrophil count was = 10000/microL. The overall response rate was 89%, with complete responses (CRs) in 52 of 120 patients (43%) and partial responses in 55 (46%). These results are consistent with previously reported outcomes from trials in this population. Of the 720 chemotherapy cycles planned for all patients, 615 (85%) were given on time at full dose. The median relative dose intensity (RDI) of cyclophosphamide and doxorubicin was 99%; the RDI of vincristine was 73%. In the 53 patients = 60 years of age, 80% of the chemotherapy cycles were given on time at full dose, with median RDIs similar to those in the entire population. Response rates in the older patients were also similar, with CRs in 24 patients (45%) and partial responses in 21 (40%). Hematologic toxicity was significant but tolerable, with no treatment-related deaths. At a median follow-up of 20.6 months, 77% of patients were still alive. Standard-dose CHOP administered every 14 days with prophylactic G-CSF support was delivered as planned in most patients and produced response rates comparable with those with CHOP given every 3 weeks, without exceptional toxicity.