The authors test the hypothesis that separation from a violent husband or partner improves maternal parenting in Japan and examine how childhood abuse history (CAH), experience of domestic violence (DV), mental health problems, husband or partner's child maltreatment, and other demographic factors affect maternal parenting after such separation. A self-administered questionnaire survey is conducted for mothers (n = 304) and their children (n = 498) staying in 83 mother-child homes in Japan to assess the mothers' CAH, DV experiences, current mental health problems, and exposure to a husband or partner's child maltreatment. The authors also assess maternal poor parenting (physical and psychological abuse, neglect, no playing, and no praise) before and after admission into the mother-child homes. The total poor parenting score (specifically for neglect, no playing, and no praise) significantly reduces after separation from a violent husband or partner (p = 0.001, paired t test). However, scores for psychological abuse significantly increase after admission (p less than 0.001, paired t test). CAH, DV, and mental health problems are not associated with a reduced total poor parenting score after admission. Husband or partner's child maltreatment is independently significantly associated with a reduced maternal poor parenting score: A 10% increase in such maltreatment is associated with a 5% reduction in the poor parenting score after separation. Marital status also contributes to the score reduction: The reduction is less in married or divorced mothers than in those who did not marry the partner. Mother-child homes might be useful for improving maternal parenting. Further study is needed to elucidate the mechanism of the impact of separation from a violent husband or partner on maternal parenting. (Contains 3 tables.)