Comparison of 659 pregnant and 202 nonpregnant women with similar demographic characteristics showed overall rates of cervical cytomegalovirus excretion that were identical (9.5% vs. 9.4%) and were surprisingly high, especially since 89% of the pregnant group possessed antibody to cytomegalovirus when admitted to the study. Prevalence of cytomegalovirus among gravidas was significantly lower during the first (1.6%) than during the third (11.3%) trimester. Thus, early pregnancy appeared to exert a suppressive effect on viral excretion that waned with advancing gestation. A similar but less significant occurrence was observed in the two groups with respect to viuria. Increasing age also appeared to suppress the virologic expression of cervical and urinary tract infection, whereas multiparity seemingly produced such an effect only in the cervix. Among both cervical and urinary excreters, a few shed virus thoughout pregnancy, and others shed virus intermittently; however, viral shedding most commonly began in late gestation and frequently continued into the postpartum period. Primary infection was not documented, and antibody status remained unchanged with the advent of viral excretion in most cases. Thus, reactivation of endogenous virus seems the most likely explanation for viral shedding in our population. Similar rates of isolation of Neisseria gonorrhoeae in excreters and nonexcreters further argue against the other major possibility, venereal reinfection.