Food stamp caseloads increased dramatically between October 2000 and October 2003. This study examines whether new program rules and procedures increased participation rates for families with children. Our results show that families recently on welfare were substantially more likely to participate in the Food Stamp program in 2002 than in 1997 or 1999. In contrast, participation rates for families with no cash welfare experience, the largest share of poor families with children, remained quite low throughout the period. The new program rules and procedures did not affect their participation. Nonparticipating families are more likely to have characteristics associated with shorter term economic deprivation than participating families, but their low current incomes and levels of economic hardship indicate that food stamps would benefit these families substantially. States could encourage more families to take advantage of food stamps by strengthening public outreach and adopting new options to simplify their programs.