One hundred forty-seven patients with Ann Arbor stages I and II diffuse large cell lymphoma (DLCL) were treated with combination chemotherapy consisting of cyclophosphamide, doxyrubicin, prednisone, and low-dose bleomycin (CHOP-Bleo) and involved-field radiation (IF XRT) between 1974 and 1984. A complete remission (CR) was attained by 54 of 57 patients with stage I disease and by 78 of 90 patients with stage II disease. Thirty-five patients had relapsing disease that occurred within 3 years in 31. The overall 10-year survival rate, counting all deaths, for patients with stage I was 72% as compared with 43% for patients with stage II (P less than .01). Determinate survival rates, censoring eight unrelated deaths, were similar to the overall survival rates: 77% and 51%, respectively. A multivariate analysis identified three independent prognostic factors: age, tumor extent, and serum lactic dehydrogenase (LDH) level. When the combined effect of tumor extent and LDH level were taken into consideration in the analysis, three risk groups for survival were identified. The best group, which consists of patients with minimum tumor and normal LDH levels, had a 10- year determinate survival of 79%. Patients with extensive tumors and elevated LDH levels had the poorest survival rate of 44%. An intermediate-risk group with a determinant survival of 62% was composed of patients with either extensive tumors or elevated LDH levels. These differences demonstrate the need to develop different treatment strategies based on risk factors for survival for patients with apparently localized Ann Arbor stages I/II DLCL.