To date, there has been little empirical evidence to support the broader use of value-based insurance design, which lowers copayments for services with high value relative to their costs. To address this lack of data, we evaluated the impact of the value-based insurance program of a US corporation, Pitney Bowes. The program eliminated copayments for cholesterol-lowering statins and reduced them for clopidogrel, a blood clot inhibitor. We found that the policy was associated with an immediate 2.8 percent increase in adherence to statins relative to controls, which was maintained for the subsequent year. For clopidogrel, the policy was associated with an immediate stabilizing of the adherence rate and a four-percentage-point difference between intervention and control subjects a year later. Our study thus provides an empirical basis for the use of this approach to improve the quality of health care.