Federal budget outlays totaled $3.5 trillion in 2009, of which somewhat less than 10 percent ($334 billion) was devoted to children. Despite increased spending on children under the American Recovery and Reinvestment Act of 2009 (ARRA), the kids' share of total outlays actually fell modestly to 9.5 percent in 2009, down from 9.8 percent the previous year. The children's share of the tax expenditure budget also declined between 2008 and 2009, from roughly 9 to 8 percent. This fourth annual "Kids' Share" report examines federal expenditures on children during an unusual year, when unemployment averaged 8.5 percent and total federal spending hit a post-World War II high of nearly 25 percent of the economy. This year's report adds a special focus on the effects of ARRA, with new analyses showing how the infusion of funds appropriated in 2009 will spend down over the next few years under current law. As their analysis shows, many children's programs are projected to reach peak spending in 2010, after which outlays will drop off--assuming that temporary ARRA outlays end as scheduled and other policies continue unchanged. Their analysis does not include the projected effects of the health reform legislation passed in 2010, which are not yet incorporated in Congressional Budget Office (CBO) projections. After an initial section explaining the methodology for estimating children's expenditures across more than 100 federal programs and tax provisions, the report presents findings in three major areas, corresponding to the present, the past, and the future. For the present, they examine outlays and tax expenditures in 2009, relying on the detailed budget data released in February 2010. (Contains 17 figures, 4 tables and 16 endnotes.)