The Patient Protection and Affordable Care Act of 2010 (ACA) includes many changes to the U.S. Federal Tax Code. The tax penalty imposed on individuals who choose to remain uninsured received extraordinary attention while the Supreme Court determined the constitutionality of the ACA. Now, the more relevant question is what impact the penalty may have on individual behavior. This paper presents information that suggests the tax penalty may provide insufficient incentive for many individuals to purchase insurance, even with premium tax credits to reduce the cost for households earning up to 400% of the federal poverty limit. The ACA also reduces the tax benefit from themedical expense deduction by increasing the threshold amount from 7.5% of adjusted gross income to 10% of adjusted gross income. This may increase the after-tax cost of purchasing health insurance, especially for healthier individuals whose medical expenses (excluding insurance premiums) are below the threshold amount, increasing the incentive to forego the purchase of health insurance and to pay the penalty instead. An approach more consistent with the aims of the ACA is to eliminate the threshold amount but limit the deduction to lower-income taxpayers.