Background: The aim of this study was to determine the cost impact of four different strategies for prevention of cytomegalovirus (CMV) disease after renal transplantation. Methods: Hospitalization data and medical resource utilization data were prospectively collected alongside two randomized trials. In the first trial, the patients were randomized to 3-month prophylaxis with either oral ganciclovir (1 g t.i.d., n = 36) or valacyclovir (2 g q.i.d., n = 35), and to the control group (n = 12) managed by deferred therapy. In the second trial, the patients were randomly assigned to 3-month valacyclovir prophylaxis (n = 34) or preemptive therapy with valganciclovir (900 mg b.i.d. for a minimum of 14 days, n = 36) for significant CMV DNAemia. The cost analysis involved all real costs directly related to CMV during the first year after renal transplantation. Results: The mean CMV-associated costs per patient were EUR 4,581, 2,577, 4,968, and 8,050 in patients in the ganciclovir, valacyclovir, preemptive, and deferred therapy groups, respectively (p < 0.001). Valacyclovir prophylaxis was significantly less expensive than any other regimen. The cost of one episode of CMV disease was EUR 7,510 per patient. Due to excessive incidence of CMV disease, deferred therapy was the most expensive strategy (p < 0.001). Conclusions: Valacyclovir prophylaxis is less expensive strategy compared with any other regimen.