We analysed the outcome of 200 patients, aged 38 (13-72) years, with aggressive non-Hodgkin's lymphoma (NHL) treated with high-dose chemotherapy followed by autologous haematopoietic stem cell transplantation (autoHSCT) in ten oncohaematological centres belonging to Polish Lymphoma Research Group (PLRG). The source of stem cells for transplantation was peripheral blood (autoPBSCT, n = 153), bone marrow (autoBMT, n = 40) or both blood and bone marrow (n = 7). The probability of overall survival (OS) and progression-free survival at 10 years was 51% (+/- 7%). The transplant-related mortality rate equalled 7%. In multivariate analysis, the only factor influencing independently the probability of OS was disease status at transplantation (p < 0.00001). The outcome of patients transplanted in first or subsequent complete remission or first partial remission (PR) was significantly better compared with subjects given autoHSCT in PR 2 or those with primary or secondary refractoriness. Regarding histological subtypes, the highest OS rate (87%) was observed for anaplastic large T cell lymphoma. The outcome after autoBMT was better compared with autoPBSCT (OS probability: 67% vs. 43%), although the difference did not reach statistical significance. We conclude that high-dose therapy followed by autoHSCT is an effective option for high-risk aggressive NHL. Remission status is a major factor determining long-term outcome. This should be taken into account when referring patients for autoHSCT.