The value of tumor angiogenesis, EGFR and c-erbB-2 oncoprotein, a long with p 53 protein expression for predicting relapse-free survival was investigated in 110 node-negative breast cancer patients. The grade of neovascularization was assessed by the microvessel density which was obtained by an immunocytochemical staining by factor VIII-related antigen. EGFR, c-erbB-2 oncoprotein and p 53 oncoprotein were also determined by immunocytochemical assay. Univariate analysis showed no statistical significance of EGFR, c-erbB-2 and p53 status as a prognostic indicator. However, the microvessel density was a significant predictor of relapse-free survival. Patients with over 100 counts of factor VIII-RA positive cells per mm2 field in the most active areas of neovascularization showed significantly poorer prognosis compared to those with less than 100 counts (p < 0.005). Multivariate analysis demonstrated that microvessel density was an independent prognostic indicator in node-negative breast cancer patients (p < 0.0005). It was suggested that microvessel density might be of use in selecting the high-risk group in node-negative breast cancer patients needing adjuvant therapies.