Background and Objective: Gastric cancer (GC) is one the most common causes of death worldwide. Despite the decreasing rate for GC in the world during recent years, it remains the most common cancer in our country, especially among men. This study aimed to assess the survival of the patients with GC and to determine the risk factors involved. Materials and Methods: A total of 400 patients with GC in the Cancer Institute of Imam Khomeini Hospital, were entered in the study during 2003 - 2007. Patients were followed up through periodical referrals and hospital visits and/or phone calls. The survival time was considered as the time period from diagnosis to either death or the end of study. The effects of various risk factors such as gender, age at diagnosis, tumor site, pathologic stage, type of treatment, and tumor size were evaluated by Cox Proportional Hazard (PH) model. Data were analyzed using SPSS16 statistical software. Results: Of the total of 400 cases studied, 303 (75.8%) were males. About one third of the patients (130 32.5%) experienced death. The survival mean and median were 41.8 3.1 and 26 months, respectively. The percentages of one-, three-, and five-year survivals were 74%, 31% and 23%, respectively. Gender, age at diagnosis, pathologic stage, and tumor size appear to be the most significant factors affecting the survival rate among GC patients. Conclusions: The majority of the risk factors, affecting the survival rate in this study, were related to the delayed diagnosis. Therefore, it seems that if the cancer is diagnosed at early stages, it may lead to better prognosis.