The Affordable Care Act (ACA) will expand access to health care for low- and middle-income Californians through two major sources: an expansion in Medi-Cal and the creation of health insurance exchanges. Under the final legislation, the exchanges will be established and run at the state or regional level. This brief estimates the number of Californians who will potentially benefit from the coverage expansion: how many will be newly eligible for Medi-Cal, for subsidized individual or small group coverage in the exchange, and for coverage in the exchange without subsidies. These estimates are based on the 2007 California Health Interview Survey, adjusted for population growth to 2016. The brief focuses on the number of Californians eligible for coverage rather than the number who will actually enroll.