Background: Funding for prevention interventions is often quite limited. Cost-related assessments are important to best allocate prevention funds. Objectives: To determine the (1) overall cost for implementing the Safe Environment for Every Kid (SEEK) model, (2) cost of implementation per child, and (3) cost per case of maltreatment averted. Design: Cost-effective analysis of a randomized controlled trial. Participants and setting: 102 pediatric providers at 18 pediatric primary care practices. 924 families with children < 6 years receiving care by those providers. Methods: Practices and their providers were randomized to either SEEK training and implementation or usual care. Families in SEEK and control practices were recruited for evaluation. Rates of psychological and physical abuse were calculated by parent self-report 12 months following recruitment. Model costs were calculated including salaries for team members, provider time for training and booster sessions, and development and distribution of materials. Results: Implementing SEEK in all 18 practices would have cost approximately $265,892 over 2.5 years; $3.59 per child per year; or $305.58 ($229.18-$381.97) to prevent one incident. Based on a very conservative cost estimate of $2779 per maltreatment incident, SEEK would save an estimated $2,151,878 in health care costs for 29,610 children. Conclusions: The SEEK model is cost saving. Cost per case of psychological and physical abuse averted were significantly lower than the short-term costs of medical and mental health care for maltreated children. SEEK model expansion has the potential to significantly decrease medical, mental health, and other related costs associated with maltreatment.