Cytomegalovirus (CMV) is the most important infection in renal transplant recipients (Brennan; JASN 2001). Exposure to the virus, as indicated by the presence of detectable IgG anti-CMV antibodies in the plasma, increases with age in the general population and is present in more than two-thirds of donors and recipients prior to transplantation (Rubin; KI 1993). In this study, all patients received renal transplant within the last 3 years, in the main Alexandria University hospital were included. Different laboratory assessment of CMV infection including, quantitative IgG, qualitative IgM, PP65 antigenemia and quantitative PCR were done. Most of our patients (38 out of 40) were positive for IgG prior to Tx; however none had prophylactic therapy. Post-Tx, only 6 had positive PCR. Half of those had CMV disease that needed therapy which was effective in two of them. The third patient who was received OKT3 at an earlier phase was not responding and died from septicemia later on. The main clinical presentation in our CMV disease patients (n=3) were nephritis, pneumonitis. However, one of the cases had an early presentation of sore throat and dysphagia a week prior to the classical presentation. All patients had +ve PCR had also +ve antigenemia for the virus, however two more patients had +ve PP65; but –ve PCR. Only 3 out of the 6 patients with +ve PCR had also +ve IgM. The total burden of CMV viral particles was correlated with the disease severity and the response to treatment. In addition, it seems to be the most sensitive and specific among the other tests use in diagnosis and predicting the outcome of CMV disease in renal transplant population. The impact of the use of new immunosuppressive drugs like MMF, OKT3 and / or the degree of the immunosuppression may play a role in both the incidence and the severity of CMV disease.