Timeline of Effective Dates of Health Care Provisions of OBBBA is Key to Understanding Impacts

Over 35 health care provisions were included in the One Big Beautiful Bill Act of 2025. These provisions span Medicaid, the Children’s Health Insurance Program (CHIP), the Affordable Care Act (ACA) marketplaces, Medicare and commercial insurance. The majority of provisions alter eligibility and spending for health care coverage under Medicaid – and take effect over the next three years. All health provisions of OBBBA will have notable impacts on coverage and care delivery in the U.S. when they take effect. The timeline of effective dates, presented in this Alert, are essential to understanding the cost and coverage impacts. 

To comply with the law, states will need to build and operate numerous additional Medicaid and ACA eligibility checks and systems by certain deadlines. Adults who live in states that have expanded Medicaid coverage under the ACA will face narrowed eligibility for Medicaid, and they may need to report monthly their hours of work or community engagement to maintain Medicaid coverage when their state implements this provision. Children of these adults could retain Medicaid eligibility separately – and need to take steps to remain enrolled. Providers will also be closely responding to implementation of the OBBBA as health provisions will impact funding, coverage for their patient populations and the amount of uncompensated care delivered in their communities.  

The following table shows the statute’s effective dates for all health provisions. Dates are listed by federal program to show the “waterfall” effect of implementation and expected impacts of the OBBBA. The table can be printed here.