IgG levels were significantly high in sera of all types of leprosy. House-hold contacts of lepromatous leprosy (LL) cases also showed significantly higher values for IgG when compared to that of control. Except polar tuberculoid (TT) cases and house-hold contacts other types of leprosy revealed a significant rise in IgA levels in their sera. IgM was only raised in borderline tuberculoid (BT) cases. C-reactive protein (CRP) was present in the sera of all types of leprosy. Highest positivity (97%) was shown by sera from erythema nodosum leprosum (ENL) cases. Rose-Waaler antibody (RA) was noted in BT, borderline leprosy (BL), LL and ENL cases. Significance of these findings is discussed.