This chapter details the impact of improved grain varieties’ use on food security. Grain crops are the dominant crops grown in Ethiopia and worldwide. Adoption or use of improved grain crops is vital for public health conditions of households in achieving food security of the public through maximizing productivity of crops mainly grown in the area. Different researchers evaluate the impact of improved grains on food security using different food security indicators and found that use of improved varieties increased consumption expenditure per adult equivalent and daily caloric intake, breaking chronic food insecurity status, in improving dietary diversity of households through increasing production productivity of the grain crops. Therefore, to achieve food security facilitating households’ research on developing improved grain crops and awareness creation of the public to adopt improved grain varieties is pivotal to enhance food security.