Medicare Part D has helped to make prescription drugs more affordable for people with Medicare, yet many beneficiaries continue to face high out-of-pocket costs for their medications. Specialty tier drugs are a particular concern for Part D enrollees in this context. This analysis draws on data from Medicare’s Plan Finder website to calculate expected annual 2019 out-of-pocket costs for 30 specialty tier drugs used to treat four health conditions—cancer, hepatitis C, multiple sclerosis, and rheumatoid arthritis.