The effect of inoculating cowpea nodule bacteria of Ethiopia on the crop performance was not evaluated with the ultimate goal of selecting effective inoculants. Fifty-one cowpea rhizobial isolates were evaluated for symbiotic performances on sand pot culture; of which eight isolates were tested on soil pot culture using five local cowpea varieties under greenhouse condition. Accordingly, 78% of the isolates displayed effective symbiosis with cowpea based on shoot dry matter accumulation. There was strong and direct correlation between nodule dry weight and shoot dry weight (r=0.892; p<0.01); and shoot dry weight and relative symbiotic effectiveness (r=0.999; p<0.01) of the inoculated plant. The symbiotic performance of ECR-0, ECR-14, ECR-24 and ECR-101 was consistent on five-cowpea varieties in soil pot experiment. Although the isolates did not show significant difference (p>0.05) among cowpea varieties, they performed slightly better on “Bole’ and “TVU” varieties. This is a promising technology to enhance cowpea production in Ethiopia, where the farmers cannot afford to buy chemical fertilizers.