Fractionation of somatic Voxexara — vitulorwmn antigen was carricd out using Sepharose 4 B gel filtration technqiue. The obtained results indicated that 4 fractions were recovered . F₁-F₄. All fractions were tested for their antigenicity by agar gel diffusion and ELISA tests. ELISA values of F₁ & F₂ were relatively similar, while F₄ had no any reactivity with agar gel diffusion and ELISA tests. Fraction 2 was usde as identified specific antigen. This anti evaluated for its diagnostic applicability against sera of infected and non infected buffalo-calves by ELISA test. The sensitivity of the test was 100% in diagnosis of confirmed infected calves. Moreover, this test could detect 38.96% of coprologically examined negative calves. It was noticed that the immune response was increased as the intensity of infection had increased.