The Medicare Part D benefit expands the universe of cancer drugs and biologics that Medicare may cover. Individual Part D plans have discretion to determine their formularies and cost sharing for drugs within federal guidelines. This paper analyzes differences in coverage and cost sharing for cancer drugs among these plans. We find that many cancer drugs, including brand-name products, are covered by almost all plans, although prior authorization might limit access to some. In addition, many plans charge a relatively low copayment for most cancer drugs. These findings suggest that Part D could greatly expand beneficiaries’ access to cancer treatments.