The results of an indirect ELISA (iELISA) and a competitive ELISA (cELISA) for detection of antibody to Brucella melitensis in cows were compared with those of conventional serological tests. The sensitivity of iELISA using 360 sera from infected not vaccinated animals was 98.3% and the specificity in 270 sera from brucellosis-free animals was 98.1%. The cELISA when tested in the same numbers of sera of the two groups were 97.2% Specific and 100 % sensitive respectively. When comparing five serological tests on 180 sera from vaccinated-infected animals, the specificity was 97.7% for cELISA, 93.8% for EDTA-modified SAT, 88.8 % for RBPT, 82.7% for SAT and 72.2 % for iELISA. It can be concluded from this study that the RBPT gave less false positive results than the iELISA in vaccinated animals and the cELISA is a good confirmatory test with the advantage of distinguishing the antibody response due to vaccination from that resulting from infection with the local Brucella isolates(Brucella melitensis) in Egypt.