Cytomegalovirus (CMV) is the most common infection complication in solid-organ transplant recipient especially kidney, and is associated with an increased risk of acute and chronic rejection. The spectrum of CMV infection ranges from latent infection to asymptomatic viral shedding to life-threatening multisystem disease. The aim of this study was to detect presence of CMV infection by laboratory studies before development of clinical features of CMV disease. We also assess incidence, diagnosis, and clinical features of CMV infection and disease along side its associated risk factors. From March 2006 to February 2008, we prospectively studied 40 kidney transplant recipients (13 female, 27 male, mean age of 40) with their donors in Sina Renal Transplant Center. All participants including donors underwent CMV IgG and IgM antibody tittering as long as CMV PCR and CMV AgPP65 detection. The same series of laboratory studies as long as physical examination, liver and renal function tests, were performed for kidney recipients only every week while being hospitalized, every other week for two months, and monthly for 6 months. Infection was defined as positive PCR, AgPP65, or CMV IgM antibody and disease was delineated as emerging signs and symptoms of CMV infection. The association of age, sex, serostatus, dialysis duration, transplant rejection and ATG administration with CMV disease and infection development was analyzed. Of the total of 40 patients, 12 patients were hospitalized after mean 15.7 weeks (range 1-35 wk) post operation because of CMV disease. 33 patients developed CMV infection with mean time of 5 weeks (range 1- 24 wk) postoperatively, of whom 17 cases were initially diagnosed to be infected using CMV PCR method.5 patients experienced acute rejection of whom 2 cases lead to graft loss. ATG administration has been shown to be statistically significantly related with disease occurrence (RR: 3.33; CI: 1.2-9.2, P<0.05). Age, sex, dialysis duration, serostatus of donors and recipients and acute rejection were statistically not significantly related with CMV disease or infection. In conclusion our study showed that 36 percent of CMV infected patients proceeded to CMV disease, so early diagnosis of CMV infection would probably reduce the prevalence of CMV disease. It seems that PCR is the most reliable method for early detection of CMV infection. In addition, we assume that postoperative ATG administration is a risk factor for CMV disease but not CMV infection development. With further increasing the number of recruited patients in successive phases of our project, the role of other measured variables in CMV infection and disease incidence is yet to be determined.