Medicaid health homes is a new optional benefit for high-need, high-cost beneficiaries with chronic physical conditions or serious mental illness, authorized in Section 2703 of the Affordable Care Act. Distinctive features of the model include the elevated importance placed on integrating physical health care with behavioral/mental health care and on linking enrollees to social services and other community supports. The Urban Institute is conducting the 5-year long-term evaluation for the DHHS Assistant Secretary of Planning and Evaluation. This initial report examines the context, design, and initial implementation challenges and successes of six programs in Missouri, Rhode Island, New York, and Oregon, the first four states with approved programs.