The federal income tax system has been used in a number of ways to promote favored forms of consumption and investment and to help selected groups of taxpayers. Since the mid-1980s, Congress has increasingly used the federal tax code to support social programs. This trend is likely to continue. We document provisions of the tax code that are aimed at low-income families including their history and recent changes. We also provide a review of literature surrounding the effect of these provisions. Finally, we discuss important differences in spending and tax programs. Understanding tax programs targeted toward low-income families is particularly important at a time when spending programs are being scaled back.