We report on long-term haematological recovery and clinical outcome after high-dose chemotherapy supported by circulating progenitor cells (CPC) transplantation in non-Hodgkin's lymphoma (NHL) patients, and analyse the role of variables which might influence engraftment. 63 consecutive NHL patients were enrolled in this study. Two groups of patients were considered for analysis: the first 34 patients had untreated diffuse large cell lymphoma with unfavourable prognostic factors. A second group of 29 patients underwent transplantation for resistant or relapsing NHL with low, intermediate and high grade histology. All patients received the BEAM conditioning regimen. As already reported in many studies, all patients showed a rapid haematological reconstitution. 43 patients (68%) achieved long-term complete trilineage engraftment within a median of 107 d from CPC transplantation. The neutrophil count was the first parameter reaching complete normalization, and haemoglobin was the last. Failure to meet the trilineage levels was due to lack of platelet recovery and was more frequent in patients transplanted in the setting of salvage protocols. By Kaplan-Meier analysis, the probability of a full reconstitution was 80% in patients to whom transplant was offered as part of a front-line therapy and 50% when transplant was given in the salvage programmes. Multivariate analysis showed that sustained long-term haematological reconstitution was significantly related to younger age, the time taken to achieve short-term reconstitution, and bone marrow involvement.