Background:Twin studies are an exceptional kind of epidemiological studies intended to determine the role of genetics as faced to the environment, to a given phenotype. Regarding the importance of increasing current knowledge in non-communicable disease so this study aims to describe details of methodology of Isfahan Twin cohort.Method: ITC is a prospective longitudinal 10 years’ cohort study that was started in 2020.Information on demographics, socioeconomic situation, health-related habits and history of disease were collected using validated questionnaires. Zygosity determined using validated questionnaires. Anthropometric measurements and blood pressure measured by trained questionnaire.During a morning visit, 4 tubes of fasting blood and a morning urine sample were collected and biochemical tests were measured in the central laboratory of the Isfahan Cardiovascular Research Institute. After the baseline phase, we will conduct biannually follow-ups by a telephone interview and a brief questionnaire that focusing on the any changes in lifestyle factors such as dietary habits, physical activity, psychological factors and smoking habits will ask. The second and last follow-ups include complete interviews similar to the baseline method with obtaining blood and biological samples.Results: Over the two years, a total of 224 monozygotic and 582 dizygotic pairs in all age groups were registered at the ITR. The number of registered participants based on age category till November 2020 was (monozygotic=14, dizygotic=82) infant’s pairs (1–24 months), (monozygotic=148, dizygotic=418) in early childhoods, late childhoods, adolescent pairs and (monozygotic =62, dizygotic =82) adult pairs. Conclusion: In this article we discussed results of preliminary data analysis on this project. More longitudinal assessments will be planned to clarify the role of genetics and the environment in the risk factors for NCDs.