Recent Phase II studies on the use of myelo-ablative chemotherapy in breast cancer have confirmed that this approach is associated with low mortality and apparent efficacy. In a preceding article the theoretical arguments were presented for testing this approach in the high-risk adjuvant setting; in the current article the clinical data justifying the present approaches for this type of treatment are reviewed. The evidence suggests that peripheral blood stem cell supported myelo-ablative chemotherapy should be tested against conventional regimens in order to determine whether or not the increased expense and toxicity of such an approach is associated with improved survival for women whose axillary node status places them at high risk of disease relapse and subsequent death.