Common bean (Phaseolus vulgaris L.) is the most widely distributed and has the broadest range ofrngenetic resources. In Ethiopia, the yield of common bean is extremely low mainly due to nitrogenrndeficiency and also little information is available regarding diversity of rhizobia nodulating commonrnbean. Hence, this study initiated to know their phenotypic diversity and maximize the symbioticrnnitrogen fixation with common bean in Eastern Ethiopia in particular, 72 isolates of bean rhizobia werernisolated from three zones, where common bean is commonly cultivated. The efficiency of infectivityrnand effectiveness of isolates was examined using the Awash Melka variety. Results revealed that 62rnisolates were able to form nodules on the roots of the common bean variety and 10 isolates failed tornnodulate the host. The tested isolates showed two different ranges of growth rates: 61 isolates as fastrngrowing and isolate NSPVR-62 from Goro Gutu woreda as slow growing. The numerical analysis ofrnthe phenotypic characteristics of 62 isolates formed two major diversity groups based on 75% level ofrnrelative similarity. The phenotypic characterization and the numerical analysis indicated that 57 isolatesrnas Rhizobium leguminosarum-like or Rhizobium etli-like, 4 isolates as Rhizobium gallicum-like and 1rnisolate as Bradyrhizobium-like rhizobia were isolated from Eastern Ethiopia soils nodulating commonrnbean. On the basis of preliminary screening of symbiotic effectiveness on sand culture from 62 isolates,rn89% of them are effective and very effective in terms of symbiotic effectiveness. Based on SDWrnyield, strains NSPVR-2 from Eastern Shewa Zone and NSPVR-26, NSPVR-29, and NSPVR-31 fromrnWestern Hararghe Zone were selected to study symbiotic effectiveness on Ayenew and Awash Melkarnvarieties on Melkassa and Babille soils. From the selected isolates, isolate NSPVR-31 showed differentrneffectiveness of nitrogen fixation on Awash Melka and Ayenew varieties. While isolate NSPVR-29rnshowed significantly (p