Whether children of separated parents 2 years of age and younger should have frequent overnight parenting time with noncustodial fathers has been the subject of much debate but little data. Contrary to some previous findings, the current study found benefits to both parent-child relationships associated with overnights (a) up to and including equal numbers of overnights at both parents’ homes, (b) for both the long-term mother-child and father-child relationships, and (c) both when children were 2 years old, as well as when they were under 1 year of age. These benefits held after controlling for subsequent parenting time with fathers in childhood and adolescence, parent education and conflict up to 5 years after the separation, and children’s sex and age at separation. While the findings do not establish causality they provide strong support for policies to encourage frequent overnight parenting time for infants and toddlers, because the benefits associated with overnights also held for parents who initially agreed about overnights as well as for those who disagreed and had the overnight parenting plan imposed over 1 parent’s objections. The observed benefits for the long-term father-child relationship are consistent with findings from intervention studies showing that fathers who are more involved with infants and toddlers develop better parenting skills and relationships with their children.