Nuclear accumulation of p53 protein is associated with a poor clinical outcome in breast cancer patients. This study was designed to determine the frequency of p53 protein immunoreactivity in primary breast cancer to correlate the presence of p53 protein with established risk factors including the estrogen receptor and progesterone receptor status, and to evaluate the prognostic significance of p53 protein immunoreactivity regarding patient survival in Taiwan. To assess the p53 protein immunoreactivity, 104 patients with breast cancer were examined using immunohistochemical methods. P53 protein was detected in 40 (38.5%) of these primary breast cancer specimens. Highly significant associations were found between p53 protein expression and negative steroid receptors, histologic grade III. There were no statistically significant references in p53 protein expression with respect to age, tumor size, lymph node status, or clinical stage. Patients with p53 positive tumor showed poorer survival but this did not achieve significance. However, there were more patients with poor survival in the axillary node-positive group (p < 0.05) than in node-negative group. This suggests that the p53 protein expression is marginal as a prognostic indicator in breast cancer with axillary-node metastasis.