Background: Low-income and racial/ethnic minority mothers and their young children are at increased risk for obesity. Lack of access to evidence-based obesity prevention and treatment services further contributes to these disparities. Methods: This two-arm, parallel, randomized controlled trial (RCT) tests the effectiveness of a simple obesity intervention (HABITS) delivered as part of ongoing home visitation services, compared to the existing home visitation services without obesity-related content on mothers' and children's obesity risks. HABITS focuses on habit formation and modifications of food and activity cues in the home to support habit formation. Habit formation is focused on improving five behaviors: 1) fruits/vegetables, 2) fried foods, 3) sugar-sweetened beverages, 4) physical activity and 5) self-monitoring. Participants will be 298 mothers (>50% African American; 100% low income) and their children (3-5yo at baseline) enrolled in a home visitation program in central Alabama. Home visitors will be randomly assigned to deliver the home visitation curriculum with or without HABITS as part of their weekly home visits for 9 months. Assessments of mothers (weight, waist circumference, and habit strength of targeted behaviors), children (rate of weight gain), and the food/activity household environment will be conducted at enrollment, post-intervention (9 month), and one year post-intervention follow-up. Discussion: This research is poised to have a substantial impact because the delivery modalities of current obesity efforts disproportionally restrict the reach and engagement of underserved, low-income children and their caregivers who are most at-risk for health and obesity disparities.