The aim of this study was to analyze the clinicopathologic characteristics of young patients with gastric cancer with special attention to hereditary gastric cancer in a tertiary referral university hospital. Charts from all patients 40 years of age or younger at the time of diagnosis, during the period from January 1, 1987 to December 31, 2001, were retrospectively reviewed. Demographic variables, family history of gastric cancer, clinicopathologic characteristics, and treatment-related variables were analyzed. Overall survival was the main outcome variable. Survival curves were constructed by means of the Kaplan-Meier method, univariate analysis was performed with the log-rank test, and multivariate analysis with Cox regression. Significance was considered at P<0.05. During the study period, 558 cases of gastric cancer were seen at our institution, 83 (14.8%) were in patients 40 years of age or younger. Mean patient age was 33.2 years. Forty-five patients (54.2%) were male. Fourteen patients (16.9%) had a family history of gastric cancer. Five patients (6%) fulfilled the criteria of hereditary gastric cancer. Surgery was performed in 88% of patients, but only 35% of the operations had a curative intent. Operative mortality was 2.4%. On univariate analysis, advanced tumor stage, hypoalbuminemia, low performance status, diffuse type, pangastric tumor location, noncurative surgery, and lack of adjuvant chemotherapy had a significant negative impact on survival. On multivariate analysis, advanced tumor stage, pangastric tumor location, and absence of adjuvant chemotherapy were significantly associated with poor prognosis. Family history of gastric cancer or hereditary gastric cancer did not have any impact on prognosis. There is a high frequency of gastric cancer in young patients at our institution. Most patients present in advanced stages, which favors a poor overall survival. Family history of gastric cancer or hereditary gastric cancer did not have a significant impact on survival. Complete resection and adjuvant chemotherapy appeared to confer the only chance of prolonged survival.