Our paper examines the prevalence and determinants of children's transitions into and out of food insecurity since 2001. We use longitudinally linked data from the Food Security Supplements to the Current Population Surveys to estimate one-year transition probabilities of entry and exit from food insecurity. Our results indicate that child hunger is typically short-lived, but children experiencing very low food security frequently experience multiple consecutive years of food insecurity. We demonstrate large demographic and socioeconomic differences in rates of entry into very low food security and persistence in children's food insecurity. Income and employment shocks are important predictors of child hunger transitions. Finally, we find that the Great Recession increased the likelihood that children entered into and persisted in food insecurity among children.