Abstract: The fusion of sp2/o myeloma cells with spleen cells from mice immunized with Leishmania donovani promastigotes produced 7 hybridoma clones.In an immunodiffusion system with subclass-specific antisera, L8G5, L9E4, and L9F5 were shown to be IgG1, whereas L7B5, L7E12, L7A6 and L7C11 were IgM. The results showed that the monoclonal antibodies were not cross reactive with other species of Leishmania and Trypanosoma.Indirect immunofluorescent antibody assay with live leishmania showed that the monoclonal antibodies recognized only the antigens bound to the surface of L. donovani promastigotes.