Purpose: The study aimed to translate the Couple Satisfaction Index (CSI 32) into Korean, to evaluate the reliability and validity of CSI 32 and short-form (CSI 16, 4) in the Korean context, and to determine a cut-off score for Korean couples. Methods: Korean Versions of the Couple Satisfaction Index (K-CSI) 32 was translated, back-translated, and reviewed by five bilingual experts. Confirmatory factor analysis (CFA) was conducted with data from a sample of 218 couples (N = 436) to test construct validity. Validity and reliability were evaluated. The receiver’s operating characteristics curve analysis was used to obtain the cut-off score. Results: The construct validities of K-CSI 32, 16, and 4 were verified using one-factor structures. The results of CFA showed a slightly better fit for K-CSI 16 and 4 than for K-CSI 32. Convergent validity was supported by significant positive correlations of K-CSI with Kansas Marital Satisfaction Scale, Dyadic Adjustment Scale, and Family Relationship Assessment Scale. Moreover, the significant differences in K-CSI between normal and depressive group demonstrated known-group validity. Cut-off scores of 105.5 on K-CSI 32, 50.25 on K-CSI 16, and 13.25 on K-CSI 4 were validated to identify distressed couple relationships. Conclusion For clinical practice, the reliable and valid K-CSI 32 has the potential to measure changes in couple satisfaction after couple therapy or interventions. Applying K-CSI 32 may facilitate research on couple and family relationships in nursing and contribute to the discussion on the role of couple satisfaction in mental health.