While CHOP therapy is effective for malignant lymphoma, the optimum schedule for elderly patients remains controversial. The present study investigated the usefulness of reduced-dose CHOP therapy for elderly patients. Previously untreated patients aged 65 years or older with intermediate to high-grade non-Hodgkin's lymphoma were given up reduced-dose CHOP therapy at 3-week intervals. Group A patients were given 5/6 of the standard dose and Group B received 7/12 of the standard dose. Filgrastim was administered when the white blood cell count fell below 2,000 mu /L, Fifty-seven patients were evaluable and the scheduled therapy was completed in 37. For patients aged from 65 to 79 years and for patients older than 80 years, the complete response rare was 79.5% and 46.2%, overall 3-year survival was 58.2% and 30.4%. and event-free 3-year survival was 49.3% and 44.4%. respectively. Major toxicities (greater than or equal to grade 3) included leukopenia in 42 patients and documented infection in 7 patients. Grade 3 cardiac plus renal failure, grade 3 peritonitis due to small bowel perforation, and grade 3 liver dysfunction occurred in 1 patient each. One patient died of toxicity (grade 4 hematological toxicity and pneumonia). In conclusion, it seems that in the elderly patients with non-Hodgkin's lymphoma, response to reduced-dose (5/6 dose) CHOP therapy is comparable to that for standard CHOP in younger adults. mainly because of improved dose-intensity.