We tested the feasibility and efficacy of a novel high-dose sequential chemoradiotherapy programme (HDS) in 14 relapsed or refractory non-Hodgkin's lymphoma patients with very poor prognostic features, i.e. transformed histology, marrow invasion, low performance status. This regimen included the sequential administration of high-dose cyclophosphamide (CY) 7 g/m2 followed by high-dose methotrexate (MTX) 8 g/m2 and high-dose VP16 2 g/m2 and finally by total body irradiation (TBI)-melphalan and autograft of bone marrow and peripheral blood progenitor cells. No hemopoietic growth factor support was employed in any phase. There was one treatment-related death during the high-dose phase; three other patients did not complete the programme. All 10 patients concluding the programme achieved complete remission, with four patients in complete clinical remission at a median follow up of 34 months. Median overall survival was 27 months and median failure-free survival (FFS) was 12 months. Twenty-six well comparable patients received conventional salvage therapy during the same period. Their projected median overall survival (8 months) and median FFS (4 months) were shorter than in the HDS group (p = 0.06 for overall survival and p = 0.03 for FFS). Thus, HDS is a feasible programme and may offer superior results than conventional therapy in poor-prognosis NHL patients.