This retrospective study was designed to evaluate the prognostic value of immunohistochemically detected nm23-expression in invasive breast cancer. Cellular expression of nm23 was assessed in 325 primary breast cancer tissues by immunohistochemistry. The data were correlated to established functional factors of prognosis (age, tumor size, nodal status, tumor grade, steroid hormone receptor status), and to clinical follow-up (median observation time, 92 months). 215/325 (66.2%) tumor tissues were considered nm23 positive. nm23 expression did not correlate to any of the investigated markers. Similar results were obtained after subdivision of the patients into node-negative patients (n=153) and node-positive cases (n=172). With respect to clinical outcome, nm23 expression displayed no statistical significance to predict the clinical course. In conclusion, the determination of nm23 expression is an independent factor but lacks prognostic or predictive value in breast cancer patients.