We evaluated the costs of unpurged autologous stem cell transplantation in a non-randomised study of 54 consecutive patients with lymphoproliferative malignancies who have been transplanted at the Nijmegen University Hospital between July 1992 and March 1998. Thirty-five patients were transplanted with autologous peripheral stem cells (APSCT): 30 had non Hodgkin's lymphoma (NHL) and 5 acute lymphoblastic leukaemia (ALL). Nineteen patients were transplanted with autologous bone marrow stem cells (ABMT): 17 had NHL and 2 ALL. The number of progenitor cells (CFU-GM, BFU-E) and nucleated cells was significantly higher in peripheral blood transplants. The duration of cytopenia was shorter after APSCT. The leucocyte recovery to 0.5 x 10(9)/L was 13 days for recipients of peripheral stem cells compared to 20 days for bone marrow recipients (P <0.001). The platelet recoveries to 20 x 10(9)/L were 13 and 29 days, respectively (P = 0.001). This resulted in significantly shorter admission duration 24 days after APSCT versus 30 days (P = 0.003) after ABMT. Furthermore, a statistically significant difference between both groups was observed for antimicrobial costs (mean: fl 2,939 vs fl 4,888; P = 0.008), platelet transfusions (median: 3 vs 7 units; P = 0.01) and erythrocyte transfusions (median: 6 vs 10 units; P = 0.03). The mean overall costs were lower in patients transplanted with stem cells from peripheral blood: fl 34,178 versus fl 43,469 (P = 0.007). This study suggests that the APSCT results in significant cost savings due to shorter hospital stay and less costs of supportive care, despite higher mobilisation costs. The costs of blood transfusions and antimicrobials for patients with ALL were significantly higher when compared to patients with NHL.