Purpose: This study aimed to verify the reliability and validity of the Japanese version of the Ethical Decision-making Climate Questionnaire (EDMCQ) for decision making in intensive care units (ICU). Methods: The Japanese version was created by translating the English version of EDMCQ. A survey was conducted by mailing the questionnaires, targeting ICU nurses. The test was retested 14 days later. Results: The test was distributed to 439 ICU nurses. Overall, 204 responses from nurses at 25 facilities were received and analyzed (effective response rate: 46.5%). Cronbach’s α coefficient for the entire scale was 0.91, and the intraclass correlation coefficient was 0.80 (n=101, valid response rate: 23.0%). The indices for model fit in the confirmatory factor analysis were CFI: 0.836, GFI: 0.783, AGFI: 0.741, and RMSEA: 0.071. Conclusion: The Japanese version of the EDMCQ can be considered to be a practical scale for evaluation of ethical climate in Japan.