Technical Abstract: Sweet sorghum [Sorghum bicolor (L.) Moench] is one of the favorable biofuel feedstocks for ethanol production. Fall armyworm [Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae)] is one of the most serious foliar-feeding insect pests in sorghum production in the southeastern US states. Severe whorl injury of fall armyworms results in significant reduction of sweet sorghum biomass accumulation. Breeding for fall armyworm-resistant sweet sorghum hybrids with high yield potential is one of the long-term goals of our research team. In the present study, 116 sweet sorghum inbred lines were evaluated for fall armyworm resistance with natural fall armyworm infestations. The experiment utilized a randomized complete block design with two replications of double-row plots. The experiment was repeated with two planting dates in 2009. Fall armyworm injury was assessed using a visual rating scale (1-9; 1 = no injury, while 9 = complete defoliation) on each row of the experimental plots. We identified 11 entries (i.e., entries 1, 2, 6, 10, 11, 15, 20, 24, 25, 27, and 29) with the lowest fall armyworm injury ratings (< 3.25), and four entries (i.e., entries 3, 4, 18, and 22) with the highest ratings (> 4.0). The rest of the 101 entries showed moderate resistance to fall armyworm feeding. The identification of the four fall armyworm-resistant sweet sorghum inbred lines is important to develop new sweet sorghum hybrids with fall armyworm resistance, and in turn, to reduce the cost of insecticide applications, and improve the long-term sustainability of sweet sorghum production in our region.