A study has been done to find the effect of purification of crude antigens extracted from adult F. gigantica and F. hepatica on the cross reactions encountered in C.I.E.P., I.H.A. and E.L.I.S.A. serological techniques with sera o other parasitic and non-parasitic diseases. It was performed on 75 patients and 20 healthy controls. It was found that sera of many diseases may cross-react with crude Fasciola antigen in serological diagnosis. These diseases include schistosomiasis, hydatidosis, amoebic liver abscess, heterophyiasis, trichinosis, non parasitic liver diseases (liver neoplasms, pyogenic liver abscess, viral hepatitis and acute leukaemic) and rheumatoid arthritis. Partial purification of crude Fasciola antigens is a suitable method to avoid cross reactivity when using C.I.E.P. or to diminish them when using E.L.I.S.A. No need for this purification when using I.H.A. So using partially purified adult Fasciola antigens C.I.E.P. was the most specific test (100%) of followed by C.L.I.S.A. then I.H.A.