Background: Beyond the immediate toll of injuries and deaths, major disasters are often associated with long-term increased risks of chronic disease. We sought to investigate the incidence of metabolic syndrome (MetS) among survivors of the 2011 Great East Japan Earthquake and tsunami. Methods: Subjects aged ≥18 years from the tsunami-stricken area participated in a prospective cohort study of disaster survivors (the RIAS Study) from 2011 to 2015. After excluding subjects who were previously diagnosed with MetS, we observed the cumulative incidence of MetS across four annual examinations among 7318 subjects (mean age, 59.8 years; 43.5% men). We defined MetS using the International Diabetes Foundation criteria. Results: The 4-year cumulative incidence of MetS was 18.0% in the overall sample. The incidence was significantly higher among older women survivors relocated to prefabricated temporary housing (40.9%, 95% confidence interval, 36.4-44.6), and other types of housing (36.2%, 95% CI: 32.3-40.6) compared to those who were not relocated (34.1%, 95% CI: 30.9-37.4). An increase in incidence of MetS was not observed for older men, or younger survivors aged ≤64 years. Conclusion: Relocation to prefabricated temporary housing was a risk factor for increased incidence of MetS in older women.