Because of evidence that failure to deliver full dose CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) may compromise the outcome of elderly patients with aggressive non-Hodgkin's lymphoma (NHL), we attempted to deliver full dose CHOP to these patients. The objective of this review was to assess the relative received dose intensity (ARRDI), toxicity and outcome of elderly patients treated with curative intent with CHOP at our centre. Charts were reviewed of all patients greater than or equal to 65 years with newly diagnosed aggressive NHL referred to the Toronto-Sunnybrook Regional Cancer Centre (TSRCC) for initial management from 1990-1995 before routine use of G-CSF. Sixty eligible patients were identified. 31 received CHOP +/- radiation (XRT), 9 other curative treatment and 20, palliative treatment. The mean ARRDI calculated on 29/31 patients receiving CHOP was .86; 41%=1.0, 24%=.90-.99, 14%=.75-.89 and 21%=<.75. During 141 cycles of CHOP, 17 (12%) episodes of febrile neutropenia (FN) occurred in 14 (45%) patients and other grade 3/4 toxicity occurred in <10% of patients. There were 3 (10%) toxic deaths. Sixteen (52%) patients required a total of 29 admissions to hospital for FN (59%) or other causes. Of the 31 patients, 16 (52%) achieved a complete remission (CR), 7 (23%) a partial remission-1 (PR-I), 2 (6%) a partial remission-2 (PR-2), 1 (3%) had no response (NR), 2 (6%) had progressive disease and 3 (10%) were not evaluable (NE), The median progression free survival (PFS) and overall survival (OS) were (16+) months and (24.5) months respectively. We found that physician biases resulted in the selection of; younger patients (median 71 vs. 80 years), patients with a better ECOG performance status (greater than or equal to 2, 13% vs. 50%) and patients with less co-morbid illness (42% vs. 90%) for attempt at curative treatment with CHOP chemotherapy. Age was never the sole reason for offering palliative treatment. In conclusion, a subset of patients over the age of 65 with aggressive NHL, who have a good performance status and minimal co-mor bid illness can tolerate full dose CHOP chemotherapy without G-CSF support. Future strategies should emphasize full dose treatment with curative intent with minimization of both hematologic and non-hematologic toxicity. Clinical studies are required to determine whether routine G-CSF support will reduce toxicity or improve outcome in this group of patients.