To learn about TANF and FSP eligibility and participation of two-parent families, the Assistant Secretary for Planning and Evaluation, U.S. Department of Health and Human Services, contracted with Mathematica Policy Research, Inc. (MPR) to conduct an exploratory study. The goals of this study were (1) to determine appropriate data sources, methodologies, and data definitions for analyzing program eligibility and participation; (2) to document how both TANF and FSP eligibility and participation rates among married-parent families differ from the rates among single-parent families; (3) to explore, for both family types, the factors that are associated with eligibility and participation in TANF and FSP; (4) to examine TANF and FSP eligibility and participation rates for cohabiting families; and (5) to suggest avenues for further research on the program eligibility and participation of married-parent families. (Author abstract)