The potential benefit of rituximab as adjuvant to high-dose therapy (HDT) has been investigated in patients under 60 years with poor-risk (age-adjusted international prognostic index at 2-3) CD20+ diffuse large B-cell lymphoma (DLBCL). The treatment consisted of four cycles of high-dose CEOP (cyclophosphamide, epirubicin, vincristine, prednisone), plus etoposide and cisplatin during the two last cycles. Peripheral blood stem cells were collected after cycle 1, and reinfused after cycles 3 and 4. Four weekly rituximab infusions were subsequently delivered. Among the 36 patients included, 30 could complete chemotherapy schedule, and 24/36 received rituximab. A complete response occured in 26/36 patients (72%). With a median follow-up of 30 months, the estimated 5-year overall survival (OS) and event-free survival (EFS) rates (mean +/- s.d.) were 65 +/- 16 and 63 +/- 15%, respectively. For the 24 patients who received both chemotherapy and rituximab, the estimated 5-year OS and EFS rates were 86 +/- 14 and 82 +/- 15%. These data suggest that rituximab after HDT is feasible. Both complete remission rate and survival curves compare favorably with the poor outcome usually observed in high-risk DLBCL patients managed with HDT without rituximab.