The recent arrival of new hepatitis C virus (HCV) drugs has brought fiscal pressures onto Medicare Part D; spending on HCV drugs in Part D jumped from $283 million in 2013 to $4.5 billion in 2014. We examined the current benefit designs for HCV drugs in Part D plans and analyzed patients' financial burden for those drugs.A cross-sectional analysis of CMS' July 2015 Part D Plan Formulary File and the Wolters Kluwer Health Medi-Span Electronic Drug File v.2.We analyzed the type and amount of cost sharing for HCV drugs and the extent to which plans apply utilization management tools. We then estimated total out-of-pocket spending for beneficiaries to complete a course of treatment.All Part D plans covered at least 1 recently introduced HCV drug, as of July 2015. Nearly all plans charged relatively high coinsurance and required prior authorization for new HCV drugs. For enrollees with no subsidy, the mean out-of-pocket spending needed to complete a course of treatment is substantial, ranging from $6297 to $10,889. For enrollees with a low-income subsidy, out-of-pocket spending varies between $10.80 and $1191.Under the current Part D benefits, HCV drug users with no subsidy face sizable financial burdens, even with catastrophic coverage and the recent in-gap discount for brand name drugs. As baby boomers-the group most likely to have HCV-join Medicare, efforts should be made to ensure patient access to these needed drugs.