Empirical evidence indicates that children living in wealthier households have better health. Food insecurity could be related to lack of adequate nutrition experienced by poor children and may be pointed out as one of the possible explanations for this relationship. This paper investigates the association between food insecurity and children's health and nutrition and the role of the former in the child health income gradient. Using data from the 2006 Brazilian Demographic and Health Survey, the results show that children living in households with food insecurity have worse nutrition and health indicators. In addition, the relationship between household income and many children's health and nutrition measures weakens but remains significant when controlling for food insecurity. Copyright © 2011 John Wiley & Sons, Ltd.