This study evaluated the impacts of a long-standing workplace health promotion (HP) program on health care utilization and costs and estimated return on investment (ROI).Analyses used a retrospective, observational cohort design based on 7 years (2005 to 2011) of health claims and HP program participation data for 3829 HP participants and 6617 controls. Inverse propensity score-weighted mixed-model regression methods were used to balance employee demographics and comorbidities by study arm.Mean monthly health care costs were $35 less for HP participants compared with controls, and results were robust based on sensitivity analyses. ROI was estimated to be $2.53 for every dollar spent on the HP program.Results support a positive impact of HP program participation with regard to reduced health care utilization and costs and a positive ROI.