Objective: To improve primary prevention of child maltreatment, the association between at-risk parents identified by maternity hospitals and local health centers and intervention outcomes was investigated. Methods: A screening program for primary prevention of child maltreatment has been implemented for parents with children aged<3 years in A Prefecture. At-risk parents are identified at maternity hospitals and local health centers. Public health nurses provide intervention to promote positive parenting through home visits, and referred to child protective centers when they suspect child maltreatment. Results: Between 2009 and 2014, a total of 2,252 new at-risk parents were identified, 956 from maternity hospitals and 1,296 from local health centers. Among these at-risk parents, 356 (15.8%) were referred to child protective centers for possible child maltreatment, 88 of which came from maternity hospitals and 268 from local health centers. The rate of referral from maternity hospitals was significantly lower than that from local health centers (9.2% vs. 20.7%, p<0.001). Conclusions: Identification of at-risk parents during pregnancy and early intervention resulted in a decrease in the rate of referrals to child protective centers. The specific risk factors of “perceived lack of social support”, “mental illness” and “teen pregnancy” may be mitigated by early intervention. J. Med. Invest. 64: 153-159, February, 2017