Full implementation of the Affordable Care Act (ACA) will add some 330,000 people to the Medicaid rolls in Washington state and a much smaller number for the Children's Health Insurance Program (CHIP). The states cost per new enrollee will be low, however, when compared with current enrollees. The new enrollees are projected to be younger and healthier, and the ACA's new eligible will require a much lower state contribution -- down from 50 percent of medical spending to zero percent initially, rising to 10 percent over time. These are the key findings among numerous projections, which combined the results of prior Urban Institute microsimulation of coverage choices and health care costs with the large population sample of the Washington State Population Survey.