Under the Patient Protection and Affordable Care Act, also known as federal health care reform, the state has the option to expand its Medicaid program (known as Medi-Cal) to cover over one million low-income adults who are currently ineligible. Currently counties have the fiscal and programmatic responsibility for the care of the low-income adult population that would be covered by the expansion. The Governor has proposed to adopt the optional expansion, but has outlined two distinct approaches to implementing the expansion—a state-based approach and a county-based approach—and has not indicated a preference for either approach. Under both approaches, the Governor indicates that the expansion will require a reassessment of the state-local fiscal relationship. We find that the expansion would have significant policy benefits, including improved health outcomes for the newly eligible Medi-Cal population. We estimate that fiscal savings to the state as a whole are likely to outweigh the cost of the expansion for at least a decade, although these estimates are subject to significant uncertainty. Despite the significant uncertainty about long-term costs and savings, on balance, we believe the policy merits of the expansion and fiscal benefits to the state as a whole likely will outweigh the costs and potential fiscal risks. We therefore recommend the state adopt the expansion. We also find that the state is in a better position to effectively deliver health services to the newly eligible population. Therefore, we recommend the Legislature adopt a state-based expansion, shifting the fiscal and programmatic responsibility of providing physical health care to the expansion population from counties to the state. Given this shift of responsibility, we further recommend the Legislature redirect a portion of funding currently allocated to counties under 1991 realignment for indigent health care.