A retrospective study was performed in liver transplant patients with high risk to develop cytomegalovirus infection (CMV D+/R-) who were treated with valgancyclovir for 3 months as prophylactic therapy. The aim of this study was to determine the safety and efficacy of prophylactic therapy with valgancyclovir. Weekly CMV antigenemia was routinely assessed during the first 3 months posttransplantation, twice a month to month 6, and monthly until the end of the first year, as well as when clinically indicated. The follow-up period was 1 year. From January 2003 to February 2007, 199 liver transplantations were performed at our institution, including 23 (11%) high-risk patients for CMV infection. Median age was 47 +/- 11.6 years. Nineteen patients (70.4%) were men. Five subjects (21.7%) developed CMV infections. Three patients with positive CMV antigenemia at 3, 4, or 6 months posttransplantation were asymptomatic, while 2 (8.7%) showed gastrointestinal CMV disease at 2 months posttransplantation or CMV hepatitis at 1 month after the end of the prophylactic therapy. Treatment with intravenous gancyclovir followed by oral valgancyclovir was successful in both patients. No opportunistic infections were observed and only 1 patient developed leukopenia as an adverse event related to valgancyclovir.