BACKGROUND Workplace wellness programs hold promise for managing the health and costs of the U.S. workforce. These programs have not been rigorously tested in healthcare worksites. PURPOSE To evaluate the impact of MyHealth on the health and costs of UPMC healthcare workers. DESIGN Five-year observational study conducted in 2013 with subgroup analyses and propensity-matched pair comparisons to more accurately interpret program effects. SETTING/PARTICIPANTS UPMC, an integrated health care delivery and financing system headquartered in Pittsburgh, Pennsylvania. Participants included 13,627 UPMC employees who were continuously enrolled in UPMC-sponsored health insurance during the study period and demonstrated participation in MyHealth by completing a Health Risk Assessment in both 2007 and 2011, as well as 4,448 other healthcare workers employed outside of UPMC who did not participate in the program. INTERVENTION A comprehensive wellness, prevention, and chronic disease management program that ties achievement of health and wellness requirements to receipt of an annual credit on participants' health insurance deductible. MAIN OUTCOME MEASURES Health-risk levels, medical, pharmacy, and total healthcare costs, and Healthcare Effectiveness Data and Information Set performance rates for prevention and chronic disease management. RESULTS Significant improvements in health-risk status and increases in use of preventive and chronic disease management services were observed in the intervention group. Although total healthcare costs increased significantly, reductions in costs were significant for those who moved from higher- to the lowest-risk levels. The contrast differences in costs between reduced- and maintained-risk groups was also significant. Matched pair comparisons provided further evidence of program effects on observed reductions in costs and improvements in prevention, but not improvements in chronic disease management. CONCLUSIONS Incorporating incentivized health management strategies in employer-sponsored health insurance benefit designs can serve as a useful, though not sufficient, tool for managing the health and costs of the U.S. healthcare workforce.