The nm23 gene is thought to play a role as an inhibitor of metastatic progression in several human cancers and its down-regulation has been associated with increased metastasis and reduced survival in some studies, though not in others. To better investigate the role of nm23 in gastric cancer (GC), the expression and prognostic impact of this gene was examined in 107 radically operated GC patients in a high risk area. The expression of nm23 was determined immunohistochemically by using the rabbit antibody anti-human nm23 protein. The expression of nm23 was detected in 40.2% (n = 43) of 107 gastric tumours and correlated with a poorer clinical outcome. In a survival analysis at 5 years, patients with nm23-positive tumours had significantly worse prognosis than patients (n = 64) with nm23-negative tumours (p < 0.05). The prognostic significance of nm23 expression was confirmed by multivariate analysis including terms for tumour stage and lymph node involvement. Our results suggest that the expression of the nm23 gene in gastric carcinoma is significantly related to tumour progression and poor prognosis at 5 years.