Ninety-four patients underwent high-dose chemotherapy with stem cell support for stage IV breast cancer. The high-dose chemotherapy consisted of the Stamp V regimen in all patients comprising cyclophosphamide, thiotepa and carboplatin (CTCb). Twenty-three patients received sequential high-dose therapies with the first consisting of high-dose melphalan and the second of Stamp V. Two patients died from chemotherapy-related complications resulting in a transplant-related mortality at 100 days of 2.2%. The progression-free survival at 3 years was 36% in patients with no evidence of disease at the first course of high-dose therapy compared with 17% in patients with remaining disease at time of the high-dose therapy (P = 0.03). There was no difference in overall survival between patients with no evidence of disease and other patients. The source of stem cells, single or double courses of high-dose therapy, positive selection of CD34+ cells, or number of involved sites had no influence on either progression-free survival or overall survival. Further studies of more intensive induction chemotherapy followed by high-dose therapy with stem cell support are indicated.