The Medicaid Drug Rebate Program is a program in the United States that was created by the Omnibus Budget Reconciliation Act of 1990 (OBRA'90). The program establishes mandatory rebates that drug manufacturers must pay state Medicaid agencies related to the dispensing of outpatient prescription drugs covered by Medicaid. To participate in the program, drug manufacturers must have a National Drug Rebate Agreement with the Secretary of the Department of Health and Human Services (HHS). As of 2020, approximately 600 pharmaceutics companies participated in the Medicaid Drug Rebate Program. Rebate amounts are confidential under section 1927(b)(3)(D) of the Social Security Act.