Both single and tandem cycles of high dose therapy and autologous peripheral blood stem cell transplantation (ASCT) have been shown to improve survival in multiple myeloma (MM) patients. We report outcomes in 104 MM patients undergoing a single transplant after conditioning with a conventional myeloablative regimen, busulphan and cyclophosphamide. The patients were either in a first (71%), or subsequent remission (29%). Peripheral blood stem cells were mobilized using cyclophosphamide and granulocyte colony stimulating factor. The conditioning regimen consisted of busulphan 0.85 mg/kg given orally every 6 h (16 doses) and cyclophosphamide 60 mg/kg/d given intravenously for 2 d. The entire conditioning, transplant and post-transplant course were in the outpatient setting for 45% patients. At a median follow-up of 26 months (range 2-98 months), the median overall and progression-free survival were 57 months [95% confidence interval (CI) 47-68] and 26 months (95% CI 20-32) respectively. Younger age and higher CD34+ cell dose infused were independently predictive of improved overall and progression-free survival. Busulphan and cyclophosphamide is an effective and well-tolerated preparative regimen for ASCT that can be given to MM patients in the outpatient setting.