Today, the Centers for Medicare & Medicaid Services (CMS) released the 2023 Transformed Medicaid Statistical Information System (T-MSIS) Behavioral Health (BH) Data Book and accompanying static tables pursuant to Section 202 of the Consolidated Appropriations Act (CAA), 2024 (CAA, 2024; P.L. 118-42). This is a publicly available compendium of the number of Medicaid and Children’s Health Insurance Program (CHIP) beneficiaries with a substance use disorder (SUD) or a mental health (MH) condition and the services they received. The report catalogs the treatment of SUD and MH in the Medicaid and CHIP beneficiary population and services provided for the treatment of SUD and MH under Medicaid and CHIP.