Infant Mental Health based interventions aim to promote the healthy development of infants and toddlers through promoting healthy family functioning to foster supportive relationships between the young child and his or her important caregivers. This study examined impacts of an Infant Mental Health home-based Early Head Start (IMH-HB EHS) program on family functioning. The sample includes 152 low-income families in the Midwestern United States, expectant or parenting a child younger than 1 year of age, who were randomly assigned to receive IMH-HB EHS services (n = 75) or to a comparison condition (n = 77). Mothers who received IMH-HB EHS services reported healthier psychological and family functioning, outcomes that are consistent with the IMH focus, when their children were between the ages of 3 and 7 years of age. Specifically, mothers in the IMH-HB EHS group reported healthier family functioning and relationships, better coping skills needed to advocate for their families, and less stress in the parenting role versus those in the comparison condition. The study also examined support seeking coping, some of which changed differently over time based on program group assignment. Overall, findings suggest that the gains families achieve from participating in IMH-HB EHS services are maintained after services cease. (author abstract)