The relationship between food assistance and inter-annual family poverty dynamics is examined using data from the 1995-2003 Panel Study of Income Dynamics. We generate expenditure-based poverty measures to examine the determinants of transient and chronic poverty, with particular focus on the differential role that Food Stamp Program (FSP) participation may have on each dimension of poverty. Results indicate that transient poverty accounts for a larger share of economic hardship than chronic poverty. Both dimensions of poverty are reduced at nearly the same rate by additional months of FSP participation. In general, the determinants of chronic and transient poverty are not found to differ significantly; both aspects of poverty appear to be correlated with age of household head, human capital, minority status, rural residence and local economic conditions.