Between 2000 and 2005, the Supplemental Nutrition Assistance Program (SNAP, until recently, the Food Stamp Program) caseload increased by half. As the Great Recession unfolded, the SNAP caseload grew even more rapidly. Further, over the past two decades the composition of the caseload has shifted sharply away from families combining food and cash assistance and toward families receiving food assistance in the absence of any other major, means-tested income support. By analyzing components of the caseload separately, we provide new and more insightful estimates of the effects of food and cash assistance policies and the economy on both the change in the composition of the caseload and the large caseload swings over the 1990s and 2000s. We find that the economy can explain a portion of caseload changes, but not compositional shifts. Food and cash assistance policies help to explain both changes. In total, the combination of SNAP and welfare policy changes account for about half of the sharp increase since 1994 in the share of SNAP households receiving food, but not cash, assistance. (Contains 4 figures, 34 footnotes, and 12 tables.)