Abstract: This paper reported the results of EBV-VCA-IgM/IgG in 38 cases of’IM’ and 43 cased of ‘Non-IM’. The postive rate of VCA-IgM and IgG were 52.63% （20/38） and 100% （38/38）, respetively in ‘IM’ group but 6.98% （3/43 cases） and 74.41% （32/43 cases） in ‘NOn-IM’ group. These results show that if we depend only on the clinical pictures, atypical lyphocyts and heterophil antibody response, some patients may be misdiagnosed. Thus, we suggest that EBV special antibodies （VCA-IgM/IgG） may be helpful in the dhagnosis of IM.