BACKGROUND: Nutritional requirements have been previously calculated for emergency-affected populations and are widely used for planning and assessing the nutritional adequacy of humanitarian food assistance. The Sphere Project is an interagency collaboration that defines minimum standards and indicators for humanitarian responses, including food and nutrition. It last published population nutritional requirements in 2004, but a revision was required due to the release of new Reference Nutrient Intakes (RNIs) by the World Health Organization and Food and Agriculture Organization (WHO/FAO). OBJECTIVE: To review and revise the list of specified nutrients and recalculate population requirements using RNIs published by WHO/FAO. METHODS: Review of published normative documents, consultation with experts and participants in the Sphere revision process, construction of a reference demographic profile, and calculation of population nutrient requirements for use in designing emergency general rations. RESULTS: Twenty-one nutrients and energy were selected for inclusion, and a demographic profile was constructed to represent a typical beneficiary population. Compared with the previous version of the Sphere Handbook, population requirements for nine vitamins and minerals were found to have increased as a result of the new WHO/FAO RNIs. CONCLUSIONS: The calculated requirements were adopted and published as part of the Sphere 2011 Handbook. The incorporation of these requirements into planning, monitoring, and evaluation practices for food assistance will help to ensure that populations receive appropriate nutritional support during crises.