The aim of this study was to identify trends in high-dose chemotherapy (HDC) with autologous hematopoietic stem cell transplantation (ASCT) and to assess survival in a large cohort of breast cancer (BC) patients receiving this therapy in Europe from 1990 to 1999. A total of 7471 patients who received HDC with ASCT between January 1, 1990 and December 31, 1999 were reported to the European Group for Blood and Marrow Transplantation Registry. Data required for demographics and survival analysis were available for 2679 patients with high-risk primary BC; 921 patients with inflammatory BC (IBC), and 2295 patients with metastatic disease. The main evaluation parameters were progression-free survival (PFS) and overall survival (OS). Between 1990 and 1998, autotransplants for BC increased 30-fold. Significant trends included use of blood-derived rather than marrow-derived stem cells, increment of reporting centers and decrease of mortality within 100 days from transplantation. The 5-year PFS and OS probabilities were 53 and 68% for high-risk disease and 42 and 53% for IBC, respectively. For metastatic disease 5-year PFS and OS probabilities in the whole cohort were 18 and 27%, respectively, while for women transplanted in complete remission the 5-year PFS was 29%. In conclusion, HDC with ASCT has been increasingly used until 1998 and the 100-day mortality rate has been constantly less than 2% from 1995 to date. The 5-year survival of high-risk BC is related to the number of axillary nodes involved at surgery. Outcome of patients with IBC is encouraging, suggesting the need for randomized trials. Patients with metastatic disease responding to pretransplant chemotherapy and harboring ER+ tumors have a better outcome.