CMV is one of the main infectious problems for SOT and HSCT. The severity of the complications are mainly associated with the type of transplant and immune status against the virus of the transplant donor and the transplant recipient. It is important to prevent exposure, using safe blood transfusion CMV seronegative donors (B1) and/or use of blood leucocytes-depleted by filtration (Al). In addition to preventing exposure, there are two widely used prevention strategies: universal prophylaxis with antiviral therapy or "pre-emptive" strategy based on the use of antivirals only to the early detection of CMV replication in blood. The first option is most used in the SOT management, especially for those identified as the high risk group of CMV disease: R (+), with D (+) or D (-) (Al), where the recommended drug is ganciclovir or valganciclovir . The second approach is preferable for HSCT, which recommends weekly monitoring for CMV viral load from day 10 to 100 post transplant (A3). This strategy requires having a viral laboratory support (A2). The selected antiviral in the case of pre emptive therapy is intravenous ganciclovir (A1).