The poor quality of available feed resources is the major limiting factor forlivestock productivity in Ethiopia. The aim of this study was to determine and compare the chemical composition of major feed resources in three agro-ecologicalzones (AEZs) of the Gera District, southwest Ethiopia. Three representative samples of natural pasture (Cynodon dactylon, Pavonia schimperiana Hochst and Rhynchosia ferruginea), three indigenous fodder trees and shrubs (IFTSs)(Erythrina abyssinica, Vernonia amygdalina and Maytenus undat), two cultivated forages (Pennisetum purpureum and Pennisetum pedicellatum) and five crop residues (Hordeum vulgare (barley), Zea mays (maize), Sorghumbicolor (sorghum), Triticum aestivum (wheat) and Eragrostis tef (Teff)) were collected from the Highland (HL), midland (ML) and lowland (LL) AEZs. The samples were analyzed for ash, dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), ether extract (EE), and acid detergent lignin (ADL) content. The results showed that different AEZs showed a significant (P < 0.05) effect on the most of the chemical composition parameters of sampled feeds. Regardless of the AEZs, the mean DM, CP, ash, EE, NDF, ADF, ADL and CF varied from 89.17% in Pennisetum purpureum to 92.22±0.51 in Erythrina abyssinica, 2.90±0.22% in Triticum aestivum to 10.70±0.52 in Vernonia amygdalina, 7.24±0.19% in Sorghum bicolor to 13.25±0.51% in Pavonia Schimperiana Hochst, 1.33±0.04% in Triticum aestivum to 2.39±0.15% in Maytenus undata, 57.65±1.19% in Erythrina Abyssinica to 79.16±1.04%in Triticum aestivum, 34.57% in Pennisetum purpureum to 59.41±0.98% in Sorghum bicolor, 8.15±0.62%in Rhynchosia ferruginea to 12.65±0.57% in Triticum aestivum and 37.51% in Pennisetum pedicelatum to 69.93±0.65% DM in Triticum aestivum, respectively. In conclusion, IFTSs had the highest CP and the lowest NDF, implying their potential as a supplement to low-quality feeds, whereas crop residues had the lowest CP and the highest NDF compared to other feed types, indicating the need for their treatment with urea or supplementing animals with protein-rich feeds, especially during the dry season.