Medicare beneficiaries could save hundreds or even thousands of dollars each year by taking less expensive – primarily generic – medicines that have been shown to be as effective and safe as more expensive brand-name products. This strategy has the potential to keep millions of seniors every year out of the Part D coverage gap known as the “doughnut hole.” This report shows that decisions beneficiaries make about their drugs, combined with their choice of a Part D drug plan, have a substantial impact on their out-of-pocket prescription drug costs.