The expression of the Her2/neu gene product p185 was retrospectively analyzed in 58 patients with gastric carcinoma. The results were correlated to various clinicopathological and prognostic factors. Positive membrane staining for p185 could be detected in 38% of the patients (22/58). Membrane staining was significantly greater in well and moderately differentiated tumors of the intestinal type when compared with poorly differentiated lesions and carcinomas of the diffuse type (P less than 0.01). Positive membrane staining did not correlate with site and tumor stage, but T1 lesions had less membrane staining than more advanced primary tumors. Overall survival showed no difference between p185-positive and negative cases. Multivariate analysis defined a subgroup of curatively resected patients with stage III and IV disease that had a statistically significant poorer survival when p185 was overexpressed (P = 0.005). Overexpression of the Her2/neu product p185 appears to be associated with intestinal-type gastric carcinoma and may help in identifying a subset of patients at increased risk for shorter survival.