Introduction: Cancers are one of the most common causes of death at age groups above 50 years old that Life style modification has an important role in prevention of them. Diets are the most important factor at the risk of gastric cancer. The aim of present study was explanation of the Experiences of Patients´ Close Relatives with Risk Factors of Gastric Cancer and Health-Therapeutic Personnel from the Determinants of Nutritional Behaviors based on protection motivation theory. Methods: The present qualitative study was done with content analysis method application at Babol health-therapeutic centers covered by Babol University of Medical Sciences for eight months in 2013. semi-structure d face to face interview were used to collect the data with 9 participants from Patients´ Close Relatives with Risk Factors of Gastric Cancer and 19 participants from Health-Therapeutic Personnel. Data analysis and collection were simultaneously done by using the method of theory-based (directed or conductive) content analysis. Results:From data analysis 487initial codes and after integration,186 main codes were extracted .This codes were pasted at 2 pre-determined categories and 7 pre-determined sub-categories related to protection motivation theory(perceived sensitivity, perceived severity, reward, fear, perceived response-efficacy, self-efficacy and perceived cost-benefit). The most main perceived problem, was the low level of awareness, attitude and practice at people about nutritional risk factors related to gastric cancer and a result the low level of disease fear. Conclusion: The findings of present study are the indicator of effective determinants on nutritional behaviors that can help to health-therapeutic policy –makers to provide and approve the most appropriate solutions and strategies with aim of changing these determinants in order to reduce nutritional risk factors related to gastric cancer.