The prevalence of maternal and congenital CMV infections is poorly documented in France. Between November 2004 and January 2005, a prospective national survey was conducted to estimate the incidence of maternal CMV infections and infections transmitted to the fetus and detected during pregnancy or at birth. It also aimed to describe the clinical and biological contexts that led clinicians to test for CMV infection. In 2003, an initial survey had shown that IgG avidity testing was performed in 98% of pregnant women in whom specific IgM antibodies were detected, in order to better determine the timing of primary infection. All laboratories performing avidity tests or direct virus detection in France provided aggregated data on CMV infection diagnoses in pregnant women, fetuses, or newborns during the study period. Systematic case reporting was conducted by a subsample of laboratories, and demographic and clinical data were collected from clinicians. To estimate the annual incidence, we considered the new cases diagnosed and reported by the laboratories in the subsample and the proportion of these cases relative to all diagnoses made in France. A total of 75 congenital infections were identified through laboratory reports. Of these, 21 were symptomatic (8 confirmed by pathological examination and 13 by clinical examination of the newborns), and ultrasound abnormalities were detected during pregnancy in 70% of these cases. The annual number of congenital infections detected during pregnancy or at birth was estimated at 277 [95% CI: 204–349]. Among these cases, 30 [95% CI: 23–37] resulted in pregnancy terminations with abnormal pathological examination, and 46 [95% CI: 33–59] resulted in the birth of symptomatic infants, corresponding to an incidence rate of 6 affected newborns per 100,000 live births [95% CI: 4–8]. During the study period, 110 primary maternal infections (PMI) were identified, most of them (73%) following routine serological screening. The annual number of PMIs diagnosed in France was estimated at 545 [95% CI: 490–600]. The survey highlighted a diversity of practices in the follow-up of PMI and the use of amniocentesis. However, our results suggest that most symptomatic congenital infections are detected in France during pregnancy or at birth. The survey data, along with additional data on the follow-up of infected newborns, would be useful to further analyze the value of systematic maternal and/or neonatal screening in France. (R.A.)