Employees' Health Cohort Study of Iran (EHCSIR) is a prospective cohort study to understand the risk factors of non-communicable diseases among a population of 10'000 public sector employees of Iran. The study population includes employees of 17 hospitals, 9 schools and 7 district health networks; all of which are related to Iran University of Medical Sciences (IUMS). It also include the staff of Ministry of Health and Medical Education.