OBJECTIVES: IMPACT trial showed that prolonged prophylaxis of 200 days with valganciclovir (VGC 200) compared with 100 days (VGC 100) significantly decreases the incidence of  cytomegalovirus (CMV) disease. Therefore, a cost-effectiveness model  was developed to evaluate  prolonged prophylaxis of 200 days with valganciclovir and its long term economic impact . METHODS: A Markov model was designed to simulate the CMV disease progression; costs and outcomes associated with the use of VGC 200 vs  VGC 100 in a cohort of 10,000 patients over 10 years was examined. Data of the disease evolution were obtained from the IMPACT  (Humar, Am J Transplant 2010) for year 1 and the available scientific evidence for years 2-10.  The analysis was conducted from the perspective of the Spanish National Healthcare System (SNHS), considering direct medical costs. Unitary costs (€, 2010) were obtained from a Spanish database. Utility values were obtained from literature. The annual discount rate was 3% for costs and outcomes. RESULTS: Treatment with VGC 200 provides better results in health than VGC 100 (50,020.30 vs. 47,639.90 QALY/patient). The average overall cost per patient is €1,121,327  with VGC 200 and €1,131,187 with VGC 100. The savings per patient treated with VGC 200  in 10 years is €986. Sensitivity analysis confirms the stability of the results. CONCLUSIONS: Treatment of patients with prolonged prophylaxis valganciclovir reduces the incidence in high risk kidney transplant recipients and is a cost-saving strategy  in CMV disease management from the perspective of the SNHS.