The 31st round of the Food Security Monitoring System (FSMS) was conducted between November 2020 and February 2021, against the backdrop of ongoing economic instability and chronic food insecurity and malnutrition. The assessment aims to ascertain the food security situation of IDP and refugee households, assess risk factors that contribute to food insecurity, and highlight vulnerable geographical areas and groups. This information on vulnerability will enable well-informed decision- making processes for programme design and targeting purposes, as well as provide evidence for the expansion of future assistance programs. The FSMS is also a major data source for the IPC, HNO and HRP. During this food security assessment, data was collected from approximately 13,000 IDP and refugee households across 135 locations in 13 states. The findings were aimed to be representative of IDP and refugee households at the cluster of camps level (around 3 camps per cluster). The survey design followed a two-stage stratified cluster sample methodology (purposive sampling followed by random sampling), in which the samples were stratified by the states and clusters. Sampling involved the use of sentinel sites, which are revisited from round to round, with households randomly selected. There are limitations to the sample as it does not include observations from urban settings and refugees from Tigray. The questionnaire included information at the household level on demographics, housing, assets, basic services, livelihoods, expenditures, coping strategies and food source and consumption. Additional information was collected on child health and feeding practices as well WFP assistance. WFP would like to thank State Ministries of Production and Economic Resources for their role in data collection, and HAC and COR for their role in field coordination.