Periodically not having enough to eat, having a diet that is inadequate, and worrying about being able to afford the amount and type of food that a household needs are all markers of food insecurity. Food insecurity persists across many households with young children and may have negative consequences for the health and well-being of infants and toddlers, who are at an especially vulnerable period in life. Overweight, paradoxically perhaps, is one of the negative consequences that may result when very young children experience food insecurity, though research findings have been inconsistent and inconclusive. This Research Brief draws on recently released data from the 9-month and 24-month waves of the Early Childhood Longitudinal Study--Birth Cohort (ECLS-B) to present a portrait of food insecurity among households with very young children in the United States. The brief also examines the indirect links through which food insecurity may affect overweight for infants and toddlers. Analyses indicate that very low food security in households with a nine-month old infant is associated with a higher likelihood of overweight later among toddlers. Very low food security is strongly associated with parenting practices, infant feeding practices, and depressive symptoms among parents, which may affect the likelihood of overweight among toddlers. This research breaks new ground by identifying these additional factors through which overweight for infants and toddlers is likely to be influenced. (Contains 5 figures and 3 endnotes.)