The Patient Protection and Affordable Care Act (ACA) will substantially increase public health insurance eligibility and alter the costs of insurance coverage. Using Current Population Survey (CPS) data from the period 2000–2008, we examine the effects of public and private health insurance premiums on the insurance status of low-income childless adults, a population substantially affected by the ACA. Results show higher public premiums to be associated with a decrease in the probability of having public insurance and an increase in the probability of being uninsured, while increased private premiums decrease the probability of having private insurance. Eligibility for premium assistance programs and increased subsidy levels are associated with lower rates of uninsurance. The magnitudes of the effects are quite modest and provide important implications for insurance expansions for childless adults under the ACA.