This paper examines the effects of the Affordable Care Act (ACA) by considering a dynamic interaction between extending health insurance coverage and the demand for federal disability insurance, which has received little attention in prior literature. I argue that as the ACA provides insurance coverage to the otherwise uninsured, it improves this group's health and reduces their demand for federal disability insurance. In order to provide a quantitative assessment of this dynamic link, I extend the Bewley-Huggett-Aiyagari incomplete markets model by endogenizing health accumulation and disability decisions. The model is calibrated to match the 2006 U.S. economy and used to examine the influence of three main components of the ACA: Medicaid expansion, insurance subsidies, and an individual mandate. Findings suggest that the ACA raises tax rates, but reduces the fraction of working-age people receiving disability benefits from 5.7 to 4.9 percent. In turn, the fiscal changes associated with disability decisions help to fund 47 percent of the ACA's cost. Results also indicate that an alternative plan without Medicaid expansion reduces tax burdens and improves welfare relative to the full package of the ACA.