Cytomegalovirus HCMV) is an agent that can cause important infections at pregnancy, in newborn period and immunosuppressive cases. Serology, culture and molecular methods are insufficient for early and practice diagnosis. Although the anti-HCMV IgM appears after antigenemia and anti-HCMV IgM, anti-HVMV IgM antigenemia can be present simultone ousley in certoin cases. The purpose of the study was to determine te presene of cytomegalovirus (HCMV) antigenemia in cases with anti-HCMV IgM. Antigenemic was investigated in 56 cases who had pregnancy, renal disease, malignancy or acute fever disease. In these cases HCMV antigenemia (HCMV pp65) was investigated by immunofluorescence method. Only one positive was determined in a patient who took chemotherapy because of lymphoma. It is concluded that the investigation of HCMV antigenemia should be made periodicallyin rather than anti-HCMV IgM in cases under risk.