To enable individualized risk-oriented adjuvant treatment of breast cancer, validated parameters are needed to help evaluate the individual relapse risk. The clinical significance of these factors is assessed by published evidence (level of evidence) and its utility in the clinical setting (utility score). The traditional prognostic factors (age, TNM stage, grading, and steroid hormone receptor status are of established clinical relevance, and their determination should be obligatory. Of the "new" tumor-biologic parameters, only the measurement of the urokinase-type plasminogen activator (uPA) and its inhibitor (PAI-1) in the primary tumor of node-negative patients has been adequately validated and can therefore be recommended for clinical application. Promising recent prognostic markers are the expression of Her2/neu, detection of disseminated tumor cells in bone marrow aspirates, various different surrogates for proliferative activity, and tumor-specific gene expression profiles. Currently, however, the data available are insufficient to allow recommendation of the parameters for routine clinical use at this time.