Poor health and developmental outcomes for children are linked to scarcity of economic resources, various barriers in the delivery of health services, and inadequate parenting. To mitigate such adverse effects and address the needs of 50 high-risk, low-income Latino and African American families receiving well-baby care at an urban primary care health center, a collaborative team from the social work, nursing, and education fields piloted a preventive two-year parent mentoring project. The intervention was theoretically anchored in the transactional model of child development. The mentoring practices used an activity-based approach for strengthening child anticipatory guidance and meeting family needs. Thirty-five intervention families completed the project. Compared with a matched community sample, intervention families showed positive statistically significant changes in parent and child outcomes. The discussion addresses the practical benefits of the intervention, limitations of the evaluation design, and implications for collaborative multidisciplinary practice.