Description: This budget and policy post responds to legislative requests for our office to estimate the costs of expanding comprehensive Medi-Cal coverage to all otherwise eligible Californians regardless of their immigration status. We estimate that nearly one million undocumented immigrants would gain full coverage under this expansion. Assuming a January 1, 2022 implementation, we estimate that the additional cost of expansion would be $790 million General Fund ($870 million total funds) in 2021-22. On an ongoing basis, we estimate the additional cost of the expansion would be $2.1 billion General Fund (nearly $2.4 billion total funds). Both our caseload and cost estimates are subject to significant uncertainty and rest on a number of key assumptions. Moreover, our ongoing estimates would be expected to change over time with medical inflation and changes in caseload and utilization.