Human cytomegalovirus (CMV) is a human herpesvirus, and infection is widespread in the human population. Prevalence of seropositivity for human CMV increases with age. CMV establishes persistent infection in vascular arterial and venous endothelial tissue. It has been associated with atherosclerosis and graft rejection in heart transplant recipients. The antiviral drug ganciclovir prevents CMV disease in heart transplant patients, and valganciclovir and CMV immune globulin reduce rejection rates and cardiovascular disease. Human CMV infection has been associated with proinflammatory cytokine increases and nonresponsiveness to antiinfluenza vaccine in the elderly. Enhanced expression of proinflammatory cytokines has also been associated with enhanced mortality in the elderly. In this issue of the Journal, Roberts et al. (Am J Epidemiol. 2010;000(00):000-000) report that, in a large population-based cohort of elderly Sacramento area Latino subjects in California followed from 1998 to 2008, more than 95% were seropositive for human CMV. In that study, Kaplan-Meier survival curves suggested worse cardiovascular disease survival for individuals in the highest quartile of human CMV immunoglobulin G antibody titers over 9 years of follow-up. Theirs is the first study known to report a relation between high human CMV antibody levels and mortality.