Food insecurity and malnutrition present key policy challenges in Ethiopia. This paper examined the determinants of food security among rural households in Ethiopia using data from the latest round of Ethiopian Rural Household Survey. Two measures of household food security (a self-reported food security status and a multidimensional index generated based on principal components analysis - PCA) were used. OLS regressions were first run to identify important determinants based on the two measures, disregarding endogeneity problems. Then Instrumental Variable (IV) estimation was carried out to account for endogeneity issues. The results revealed that age and education of household head, adequacy of rainfall, livestock possession, participation in off-farm activities, soil conservation practices and per capita consumption expenditure were strongly and positively related to household food security; while access to credit and remittance had a negative influence. Accordingly, the study suggests that a judicious combination of interventions that enhance income diversification opportunities in rural areas through promoting off-farm activities, education, training and extension services, and improving livestock productivity could help enhance household food security. Provision of awareness creation on better and productive utilization of such resources as credit should also be emphasized in rural areas.