Six exotic herbaceous forage legumes namely, Desmodium uncinatum (desmodium), Lablabrnpurpureus (lablab), Medicago sativa (alfalfa), Trifolium repens (white clover), Vigna unguiculatarn(cowpea) and Vicia dasycarpa (common vetch) were induced for nodulation on Dembia andrnWegera soils for which all except, desmodium and white clover legumes nodulated their host.rnFrom the nodulated legumes, nineteen isolates were isolated and characterized based on theirrnmorphological, cultural, and physiological properties. In the preliminary screening eleven isolatesrnof alfalfa, three isolates of vetch were assigned as fast growing Sinorhizobium meliloti and R.rnleguminosarum var viceae respectively. The isolates of lablab (three) and cowpea (two) werernassigned as slow growing Bradyrhizobium species. The vetch isolates AUVR11, AUVR13 fromrnWegera and AUVR14 (R. leguminosarum var viceae) from Dembia and alfalfa isolates AUMR3rnand AUMR10 from Wegera; and AUMR9 from Dembia (S. meliloti) were found to renodulaterntheir respective hosts. The nodulating isolates were studied with respect to their relativerneffectiveness in nitrogen fixation. Inoculation of vetch by R. leguminosarum var viceae showedrnsignificant differences in percent effectiveness (30%-83%) on vetch, and (50-100%) on alfalfa.rnAUVR13 (vetch) and AUMR9 (alfalfa) were found to be the most efficient strains withrnpercentage effectiveness of 83% and 100% respectively. Although the performance of the vetchrnisolates on two different soils showed that there was no any inter strain difference on each soil,rnDembia soil responded better in SDW and TN than Holetta soil indicating that some soil-relatedrnfactors such as pH affect symbiotic effectiveness. Generally, the fact that the number of infectivernand effective isolates of the introduced legumes in Dembia and Wegera weredas was very smallrnmay necessitate more exhaustive screening in different regions and the need for inoculation withrneffective exotic endosymbionts to fully realize the potential of Biological Nitrogen Fixation inrnforage production in animal husbandry.rnKey words/Phrases: Introduced forage legumes, Nitrogen fixation, Nodulation,rnRhizobium leguminosarum var viceae, Sinorhizobium meliloti, Bradyrhizobium spp