The increasing cost of prescription drugs is a burden for patients and threatens the financial stability of the US health care system. Rebates are a form of price concession paid by a pharmaceutical manufacturer to the health plan sponsor or the pharmacy benefit manager working on the plan’s behalf. Proponents argue that rebates result from vigorous negotiations that help lower overall drug costs. Critics argue that rebates have perversely increased the costs patients pay out of pocket, as well as the costs for Medicare as a whole. This special communication discusses how the availability of rebates for drugs covered by the Medicare Part D program may raise costs for patients and Medicare while increasing the profits of Part D plan sponsors and pharmaceutical manufacturers. Two policy alternatives are herein proposed that would reconfigure cost sharing to lower patient out-of-pocket costs and reduce cost shifting to Medicare.