Recent studies have explored feasibility and cost considerations of administering high-dose chemotherapy with hematopoietic support in the outpatient setting. Between October 1991 and April 1993, we studied 110 women with primary metastatic breast cancer undergoing high-dose chemotherapy with hematopoietic support. Ninety-two patients were managed in an outpatient clinic after high-dose chemotherapy and autologous bone marrow transplantation and peripheral blood progenitor cells. The remaining 18 patients received the same high-dose treatment and hematopoietic support in the hospital and were discharged to a nearby hotel each night; these patients were the pilot group for this effort and also served as a control group. High-dose chemotherapy consisted of cyclophosphamide/cisplatin/carmustine. Chemotherapy was well tolerated, allowing 95% of 65 eligible patients enrolled since November 1992 to be discharged soon after chemotherapy for outpatient posttransplant support. Approximately 70% of these patients required either no hospital readmission or brief readmissions of 1 to 4 days. Median days of hospitalization required for historical groups of patients receiving high-dose chemotherapy plus bone marrow support as inpatient therapy, high-dose chemotherapy with colony-stimulating factor-primed peripheral blood progenitor cells and autologous bone marrow transplantation as inpatient therapy in a traditional transplant model, and outpatient management of autologous bone marrow transplantation patients were 37, 24.5, and 7 days, respectively, despite the same high-dose chemotherapy. Charges related to the transplant procedure were reduced by 50% over the last 2 to 5 years using the outpatient management approach. This procedure may be applicable to patients with other forms of cancer receiving intensive chemotherapeutic regimens. The use of outpatient management in a transplant setting is highly cost effective.