Abstract Millions of people in developing and middle-income countries continue to experience food insecurity daily. A growing number of studies have associated food insecurity with poorer health outcomes using cross sectional data and household level data. Few of these studies have looked at longitudinal relationship between food insecurity and health outcomes. This study analyses the relationship between food insecurity and child health outcomes in middle and low-income countries using a longitudinal macro level data. The study also introduces two unique instrumental variables, size of arable land and openness to trade, to estimate this relationship. The regressions confirm previous study results that food insecurity has a significant positive relationship with child anemia and child mortality. Food insecurity has a significant negative relationship with life expectancy. Using the instrumental variable approach shows that the estimates are greater than when no instruments are used. Our work suggests that previous studies have underestimated the impact of food insecurity on child health outcomes.