Competitive ELISA test was used in this study to identify brucella antibodies in cattle sera in Mosul, and assessing the results that are given by Rose-Bengal test. Results of testing 126 cattle sera revealed that the seroprevalence was 16.7% using C-ELISA and 18.3% using RBT. There were differences in seroprevalence according to sex of animals, females showed higher seroprevalence than males, it was 19.1% and 20.2% in females and 9.4% and 12.5% in males by C-ELISA and RBT respectively. Also there were differences in seroprevalence according to age of animals and pregnancy status of females. Kappa value revealed that there was little agreement between C-ELISA and RBT, (Kappa value was 0.229). RBT was not accurate in giving real seroprevalence, since there were 13 false-negative samples from 21 samples positive with C-ELISA, and there were 15 false-positive samples from 105 samples negative with C-ELISA. Results of tube agglutination test and 2-Mercaptoethanol test indicated a decline of titers from those of previous studies, lower titer of TAT was 1/10 (19.05%) and most of titers were lower than 1/40 (76.2%) in 2-Me test. This study concluded that the brucella antibodies in cattle sera in Mosul was increased from previous years and most of cases were acute.