Hydatidosis caused by metacestode stage of Echinococcus granulosus is one of the most important cyclozoonotic disease affecting both humans and livestock resulting in considerable economic losses to livestock industry which amounts to US$ 3 billion annually (WHO factsheet on Echinococcosis, 2018). No reliable immunodiagnostic method is available for its sero-detection in animals. Native antigen-B represents one of the most immuno-dominant antigens in hydatidosis, therefore assessment of recombinant antigen-B subunit 8 was taken in the current study. The immuno-reactivity of recombinant 29-kDa EgAgB-8 protein was confirmed in the Western blot with rabbit anti-histidine antibodies and buffalo sera positive for hydatid infection. The sero-diagnostic potential of this recombinant protein was evaluated by indirect ELISA and DOT-ELISA platforms by screening two hundred and fifty buffalo sera where 44.8% (n=112) samples were revealed positive by indirect-ELISA by detecting antibodies against this antigen in sera. Immuno-reactivity with hydatid positive buffaloes (n=12) was also confirmed in DOT-ELISA. Cross-reactivity of the recombinant antigen with field sera positive for Gigantocotyle explanatum, Paramphistomum epiclitum and Gastrothylax crumenifer was also studied in DOT-ELISA that showed some of the buffaloes infected with parasites other than hydatid metacestode were cross-reacting with the recombinant antigen.