<i>Objective:</i> Our purpose was to assess the impact of prenatally diagnosed ventriculomegaly (VM) on the course of advancing pregnancy and the postnatal outcome of affected fetuses. <i>Methods:</i> In this retrospective survey 109/28,935 (3.8 per 1,000) singleton pregnancies with abnormal width of the fetal lateral ventricle system diagnosed by antenatal ultrasound examination at the University Hospital of Schleswig-Holstein, Campus Lübeck, were reviewed between 1993 and 2007. Clinical data and pregnancy outcome information were derived from a standardized parental questionnaire or from hospital records. Postnatal follow-up was obtained in >90%. <i>Results:</i> Forty-seven cases with isolated VM (IVM; 43%) and 62 fetuses (57%) with nonisolated VM were diagnosed. In the IVM group 19 cases had mild and 28 fetuses severe VM. Of 62 cases with non-IVM there were 32 with mildly dilated ventricles and 30 had severe enlargements. Chromosomal aberrations were present in 5 fetuses (4.6%) of the non-IVM group. Thirty-four pregnancies (31%) were terminated on parental request (10 IVM/24 non-IVM). The risk of abnormal neurodevelopmental outcome was highest in the presence of associated anomalies (irrespective of the extent of dilatation) and in cases with severe IVM (91 and 68%, respectively). In contrast, 13/14 children with mild IVM showed an age-related normal psychomotor behavior. Fetuses with severe VM had a 2.2- (IVM) to 3.6-fold (non-IVM) elevated risk of progressive dilatations compared to mild VM. In our study the fetuses with asymmetrical bilateral IVM tended to have severe ventricular enlargements more often. <i>Conclusions:</i> As reported previously we found a positive association between neurodevelopmental delay and the degree of lateral ventricular dilatation. The presence of additional abnormalities is generally a poor prognostic sign and accompanied by a nonfavorable postnatal outcome.