The U.S. 2010 Patient Protection and Affordable Care Act (ACA) exempts members of health care sharing ministries (HCSMs) from the individual mandate to have minimum essential insurance coverage. Little is generally known about these religious organizations and even less critical attention has been brought to bear on them and their ACA exemption. Both deserve close scrutiny due to the exemption's less than clear legislative justification, their potential influence on the ACA's policy and ethical success, and their salience to current religious liberty debates surrounding the expansion of religious exemptions from ACA responsibilities for both individuals and corporations. Analyzing documents of the United States' three largest health care sharing ministries and related material, I examine these organizations and their ACA exemption with particular consideration of their ethical dimensions. Here a thick description of the nature and workings of health care sharing ministries precedes a similar account of the ACA exemption. From these empirical analyses, five ethical and policy concerns emerge: (1) the charity versus insurance status of these ministries; (2) the conflation of two ACA religious exemptions; (3) the tension between the values of religious liberty and of justice; (4) the potential undermining of ACA policy goals; and (5) the questionable compliance of health care sharing ministries with ACA exemption requirements. An accurate and informed understanding of HCSMs is required for policymakers and others to justify the ACA exemption of health care sharing ministry members. A sufficient justification would address at least the five ethical and policy concerns raised here.