Introduction & Objective: Gastric cancer is the fourth most common and the second most deadly cancer worldwide. Surgical removal is the only therapeutic option for gastric cancer, which may be through endoscopic mucosectomy or through the more limited laparoscopic methods or open surgery. This study aimed to evaluate the different dimensions of quality of life in patients with gastric cancer who underwent gastrectomy surgery.Materials & Methods: In this study, the data collection tool was the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire and a self-generated questionnaire for recording the pathological and clinical findings of the patients. The quality of life questionnaire was completed using face to face interviews of the researcher with the patients (before the surgery and 6 months after it) and with the control group. Clinico-pathological questionnaire too, was completed through the information gathered from the patient's records. Finally, the data were analyzed by SPSS software, using descriptive statistical tests, chi-square test and non-parametrical tests in some items.Results: Totally the quality of life in 54 patients with gastric cancer (before the gastrectomy and 6 months after it) was compared with the control group. The control group was consisted of patient's kin or entourage. The analysis showed that physical function (P=0.001), emotional function (P<0.001), social function (P<0.001), cognitive function (P<0.001), and role function (P=0.013) of patients, 6 months after the gastrectomy surgery had statistically significant improvement. But in the control group, there was no statistically significant improvement in different dimensions of quality of life 6 months later. Furthermore, symptoms such as Fatigue, nausea, pain, loss of appetite, sleep disorders, constipation, and dyspnea were better 6 months after the surgery.Conclusions: Given the high prevalence of gastric cancer and its different social and psychological damages, it seems necessary to conduct various studies in order to achieve the proper ways for improving the quality of life in patients with gastric cancer and all other cancers; studies that can evaluate and monitor the effectiveness of different therapeutic methods in terms of improving the quality of life and achieving a complete remission in patients.