Objective: In recent years, the patterns of mortality have changed in Iran, and cancers are playing a greater role in this regard in this country. Various reports indicate that gastric cancer is highly prevalent; it is the second most common cancer in men, and fourth in the general population. The purpose of this study was to determine the 5-year survival rate of gastric cancer patients who had undergone surgical treatment at one of the most important cancer treatment centers, the Iran Cancer Institute, and to assess its associated factors. Methods: Three hundred and thirty patients with gastric cancer who had been admitted to and operated on at the Iran Cancer Institute, Iran between January 1996 and April 2000 were enrolled in this study. The patients' life expectancy after surgery was determined, and its relationship with variables of age at the time of surgery, gender, and factors related to the disease such as the cancer site, pathologic type, stage, presence of metastasis, and sites of metastases were assessed. Results: The 5-year survival rate in the studied patients was 23.6%, and the median life expectancy was 19.9 months. Univariate analysis showed that gender, cancer site, and pathologic type did not affect life expectancy significantly. However, the 5-year survival rate significantly decreases with age. As expected, those involved with metastasis had a significantly lower 5-year survival rate, and the disease stage significantly affected the patients' life expectancy (p < 0.001). The Cox proportional hazards model was used to assess the effect of different variables simultaneously, and it showed that age, lymph node metastasis, and disease stage influenced the rate of survival. Conclusions: Gastric cancer patients in Iran have a low 5-year survival rate. One of the most important reasons seems to be delayed consultation and diagnosis. Most patients are seen first with the disease in the late stages. At this point, most have lymph node and liver metastasis, which makes treatment even more complex. Thus, it is necessary to employ mass media for extensive public education about the early warning signs of the disease and performing periodic examinations.