Field pea (Pisum sativum) is widely cultivated in Ethiopia as a source of protein and integrated in croprnrotation to improve soil fertility for it fixes nitrogen with rhizobia. However, effectiveness in nitrogen fixationrndepends upon the selection of symbiotically effective rhizobia to enhance production. Thus, a study wasrnconducted to evaluate the performance of three inoculants; FBR 11, FBR 15, FBR 23 on growth, nitrogenrnfixation and yield under greenhouse and field conditions in relation to a commercial rhizobial strain 1018 atrnKulumsa Agricultural Research Center during 2015/16 growing seasons. Standard physiological andrnbiochemical tests were conducted to look into the nodule occupancy (competitiveness) of the three inoculantsrnagainst the local rhizobia in the soil. The study showed that Isolate FBR 15 was the most effective inoculantsrnwith nodule occupancy of 75%, and were highly effective under greenhouse conditions, whereas the otherrninoculants were effective and occupied 50-60% of the nodules of the inoculated plants. Inoculation of field pearnshowed a highly significant (pâ‰¤0.001, pâ‰¤0.01 and pâ‰¤0.05) effect on all parameters compared to the uninoculatedrnplants in the field trial. Accordingly, plants inoculated with isolate FBR15 and Strain 1018 showedrna significant increase in nodule number (84-112NN/plant (10 times), NDW (77-94mg/plant) (12 times) againstrnthe un-inoculated control plants, and they also showed a 20-25% increase in both parameters in comparisonrnto FBR11 and FBR23 inoculated plants. The treatments with FBR15 and the reference strain 1018 alsornshowed significant difference in grain total nitrogen and N uptake and straw N uptake, and seed protein withrn50-100% and 12-20% difference from the un-inoculated control plants and other Rhizobium treatments,rnrespectively. Positive correlations were observed with respect to the number of nodule and shoot dry weight (rrn= 0.49, p