The aim and objective of the study is to compare the efficacy of conditioning regimens with or without high-dose radiotherapy for treating aggressive non-Hodgkin's lymphoma (NHL). Eighty-nine aggressive NHL patients who underwent high-dose therapy in combination with autologous stem cell transplantation (HDT/ASCT) between 1993 and 2006 were retrospectively studied. HDT was either high-dose chemotherapy alone (CT) or high-dose chemoradiotherapy (CRT). Overall, 37 patients in CT group and 52 in CRT group. The median radiotherapy DT in CRT group was 8 Gy. The median count of reinfused CD34+ cells was 6.26 x 10(6) and 22.16 x 10(6) cells/kg, respectively (p < 0.001). The median time of leukocyte engraftment was 11 days in CT group and 13 days in CRT group (p = 0.003), and the median platelet engraftment time was 12 days in CT group and 11 days in CRT group (p = 0.305). The median event-free survival (EFS) was 102 and 84 months in CT and CRT groups, respectively (p = 0.783), and the median overall survival (OS) was 102 and 121 months in CT and CRT groups, respectively (p = 0.857). Prolonged hospitalization favored EFS (p = 0.013) and OS (p = 0.011). In conclusion, when compared with CT, high-dose CRT does not improve prognosis.