Grain sorghum yields are very low in eastern Africa with national mean yields of 0.6 to 1.5 Mg ha-1 compared to 4.3 Mg ha-1 in the USA where yields occasionally exceed 10 Mg ha-1. Forty three biotic and abiotic constraints were evaluated for Ethiopia, Kenya, Uganda, Tanzania and Mozambique. It was assumed that, in the absence of stress due to these 43 constraints, a mean grain yield would be 6.3 Mg ha-1. Soil water deficit accounted for about 1,800,000 Mg yr-1 of loss for these countries with deficits during grain fill of great importance in Ethiopia and Mozambique. Nitrogen deficiency and the stalk borer complex each accounted for more than 1,000,000 Mg yr-1 of grain yield loss Another 900,000 Mg yr-1 of yield loss was attributed to both striga and other weeds. Quelea, other birds, shoot fly and phosphorus deficiency were each found to cause losses of greater 500,000 Mg yr-1. Soil water deficits were important in all countries although the growth stage most affected by stress varied across the 30 production areas that were characterized. The results are presented in tables and maps grouped as diseases, insect pests, edaphic, and other biotic and abiotic constraints. The results are published in Atlas of Sorghum Production in Five Countries of Eastern Africa available at www.intsormil.org.