Introduction - The objective of this study is to analyze clinical and epidemiological data on diaphragmatic malformations and to evaluate the effectiveness and impact of prenatal diagnosis. Materials and Methods - A retrospective study was conducted using data from the Alsace Congenital Malformations Registry (Bas-Rhin department) between 1995 and 2004. Results - Sixty-five diaphragmatic malformations were identified (prevalence of 0.5 per 1,000 births), including 56 diaphragmatic hernias and 9 diaphragmatic eventrations. Hernias are more frequently left-sided (41/56, 73%), whereas there is a predominance of right-sided eventrations (8/9, 89%). Sixty-two and a half percent of hernias and 44.4% of eventrations are associated with other congenital malformations. A chromosomal abnormality was identified in 10 cases of hernias and 1 case of eventration; the most common chromosomal abnormality was trisomy 18. Twenty-nine hernias (52%) and one eventration (11%) were diagnosed by prenatal ultrasound. Discussion-Conclusion - Diaphragmatic hernia is a common malformation in newborns and young children, with a prevalence of 0.44 per 1,000 births. Prenatal ultrasound diagnosis of diaphragmatic anomalies remains challenging, with an average detection rate of less than 50%. Due to the high proportion of associated malformations, a systematic evaluation of malformations and cytogenetics is required for diagnostic and prognostic purposes. The postnatal prognosis remains guarded, particularly for diaphragmatic hernias, which have an overall survival rate of 55%. (R.A.)