We examined the relationship between nm23 expression and clinicopathological variables in 144 patients with invasive breast cancer to assess the role of nm23 expression in estimating prognosis. Expression of nm23 was significantly associated with axillary lymph node (AX) metastases (p=0.0359) and internal mammary lymph node (IMN) metastases (p=0.0146), but not with age, menopausal status, histological type or grade, or tumor size. A univariate study revealed that survival significantly correlated with tumor size, AX and IMN metastases, whereas nm23 expression did not appear to be a significant prognostic factor. Among patients with negative AX, however, survival in patients without nm23 expression was lower than in those with nm23 expression (p=0.0778). Survival in patients with IMN metastases was significantly lower than those without IMN metastases among patients with positive AX (p=0.0073). In a multivariate study, AX and IMN metastases, and nm23 expression appeared to be significant prognostic factors for survival. This study suggests that nm23 expression may be an additional prognostic factor in patients with negative AX, while IMN metastases are an additional prognostic factor in those with positive AX.