Brucellosis is still one of the most important diseases which seriously affect animals and man alike. In Egypt, Br. abortus was the commonly isolated species until the beginning of the 1970s (Zaki, 1943, Roushdy 1944, Kamel 1965, El-Gibaly 1969 and Sayour et al. 1970). In the following years, Br. melitensis became increasingly isolated (Shawkat, 1973; El-Olemy 1974; Awad et al., 1975; El-Gibaly et al., 1977, Nada, 1982 and Refai et al., 1988). Serological tests are performed using Br. melitensis biovar 1 (which is A.antigen dominant)in many countries while brucellosis infection is caused by M-antigen dominant Br. melitensis biovar 3 in our country. From that point of view, antigens were prepared from both Br. abortus and Br. melitensis and used in the present study to evaluate their efficiency in the diagnosis of the disease in animals.