When infected with Leishmania species, patients develop specific antibodies that constitute the basis of serodiagnosis. using Western blot analysis we studied the specificity of anti-leishmania donovani antibodies in patients with visceral leishmaniasis, healthy subjects living in an endemic and non-endemic areas, and patients of other infectious diseases like malaria, leprosy, tuberculosis and tropical splenomegaly. Sera from patients with kala-azar recognised numerous antigens that had a molecular weight of 150 KD, 145 KD, 120 KD, 92 KD, 87 KD, 72 KD, 65 KD, 56 KD, 50 KD, 40 KD, 26 KD, 21 KD, 14 KD, AND 12 KD. The 150, 145, 120, 92, 87, 81, 65, 25, 21, 14, and 12 KD antigens had the greatest specificity for kala-azar sera while the bands of molecular weights 72, 56, 50, and 40 KD were found to be cross reactive with sera of patients of other diseases.