BACKGROUND: This cohort was established to evaluate whether 38-year radiation exposure (since the start of nuclear reactor operations) is related to cancer risk in residents near three near nuclear power plants (NPPs). METHODS: This cohort study enrolled all residents who lived near (within 8 km) of any of the three NPPs in Taiwan from 1978 to 2016 (n=214,502; person-years=4,660,189). The control population (n=257,475; person-years=6,282,390) from three towns comprised all residents having lived far (more than 15 km) from all three NPPs. Radiation exposure will be assessed by computer programs GASPAR-II and LADTAP-II by following methodologies provided in the USNRC regulatory guides. We calculated the cumulative individual tissue organ equivalent dose and cumulative effective dose for each resident. This study presents the number of new cancer cases and prevalence in the residence-nearest NPP group and control group in the 38-year research observation period. CONCLUSIONS: TNPECS provides a valuable platform for research and opens unique possibilities for testing whether radiation exposure since the start of operations of nuclear reactors will affect health across the life course. The release of radioactive nuclear species caused by the operation of NPPs caused residents to have an effective dose between 10(-7) and 10(-3) mSv / year. The mean of cumulative medical radiation exposure dose between the residence-nearest NPP group and the control group is not different (7.69±18.39 mSv and 7.61±19.17 mSv, p=0.114).