The question as to what proportion of the welfare caseload should be required to work—and for how many hours—has become one of the most contentious aspects of the welfare reauthorization debate. The Bush Administration has proposed substantial increases in the work participation requirements that states must meet in order to receive the full amount of their welfare block grants. Legislation recently passed by the House of Representatives contains most of the work-participation provisions proposed by the Administration, with a few important modifications. There are also a number of alternative plans under consideration as the Senate turns its attention to welfare reauthorization. This analysis compares the estimated effects of some of these proposals.