ObjectivesZZThe aim of the study was to develop a North Korean version of the Composite International Diagnostic Interview (NK-CIDI) and to evaluate the reliability and validity of NK-CIDI. MethodsZZSubjects were 100 North Korean defectors, aged 18 to 65, who were recruited in a center for defectors in the National Medical Center or who were on an education curriculum in the defector settlement support center. NK-CIDI was developed based on the Korean version of CIDI considering the sociocultural background of North Korea. Inter-rater reliability, test/retest reliability, and validity of NK-CIDI were evaluated and kappa value was calculated. ResultsZZDifferent vocabularies and awkward expressions were adjusted, and additional explanations were supplemented for difficult phases. The target for development of NK-CIDI was early defectors who entered South Korea less than 3 months ago. Inter-rater reliability (n=30, kappa value 0.35–1.00), test/retest reliability (n=30, kappa value 0–0.86), and diagnostic validity (n=100, kappa value -0.02–0.42) were evaluated. ConclusionZZCompared to the general population, defectors experience more psychiatric issues, and a standardized tool for diagnosis is needed. In this study, NK-CIDI was developed and the results suggest that reliability is acceptable but validity needs further verification. NK-CIDI could be utilized in future epidemiologic studies.