Advanced stage follicular small cleaved and mixed cell lymphoma is characterized by relapse from remission and survival ranging from 6 to 12 years. Because young patients have the greatest compromise in longevity, the efficacy and toxicity of high-dose radiochemotherapy and bone marrow transplantation after conventional chemotherapy was evaluated in a prospective phase II clinical trial. Thirty-seven patients in a minimal disease state after conventional chemotherapy received fractionated total body irradiation and high-dose etoposide and cyclophosphamide, followed by purged autologous bone marrow. A reference sample of 188 patients of similar age, stage, and histology managed at this institution before 1988 was identified for comparison of patient characteristics and outcomes. Compared with reference patients, transplant recipients had a higher tumor burden at diagnosis. With a median follow-up of 6.5 years, the estimated 10-year survival after transplantation was 86%. There was a single lymphoma death yielding a 10-year disease-specific survival of 97%. There were 2 early transplant-related deaths and 2 late acute leukemia deaths. Ten patients relapsed, one with microscopic disease only. High tumor burden at diagnosis and incomplete response to chemotherapy adversely influenced survival in the reference but not in the transplanted patients. The estimated risk of death of 14% and relapse of 30% at 10 years in our transplanted follicular lymphoma patients, the majority of whom had high tumor burdens, compares favorably with our observations in appropriately matched reference patients.