Aim: To identify the predictors of nurses' family-centered care (FCC) practises in neonatal intensive care units (NICUs) in Japan. Methods: A quantitative cross-sectional survey was conducted by administrating a self-reported questionnaire to 30 nurse managers and 710 staff nurses in 30 NICUs in Japan. A facility-level questionnaire, including items about the philosophy, policies, and environment of the NICU, was administered to the nurse managers. The Japanese version of the Measure of Processes of Care for Service Providers and the Japanese version of the Measure of Beliefs about Participation in Family-Centered Service were administered to the staff nurses to assess their practise of FCC and their beliefs about FCC, respectively. The data were analyzed with descriptive statistics and multiple regression analyses. Results: Self-efficacy, neonatal care experience, FCC principles, and a 24 h parental visiting policy were significant predictors of the practise of FCC. Moreover, neonatal care experience, nursing support for the family to participate in the child's care, and visits by siblings were significantly associated with nurses' self-efficacy to implement FCC. Conclusion: Nurses' self-efficacy and hospital policies, including family visitation and participation in the child's care, were associated with nurses' FCC practises. These results suggest that educational programs to promote nurses' self-efficacy are essential and that organizational support is a key component in implementing FCC.