Objectives of the study: to analyse the features and outcomes of different types of atrioventricular septal defects, detected during fetal life, as compared to postnatal data. Material and methods: We analysed retrospectively the data concerning 82 fetuses with atrioventricular septal defect, diagnosed from 19 through 37 weeks gestation with a median of 26 weeks. In 46 cases (56.1%), the diagnosis has been made before the age of 24 weeks. Results: Characteristics of the series – in 44 fetuses the atrioventricular septal defect was not associated with other cardiac anomalies, while 38 fetuses had a more complex form. Chromosomal anomalies were present in 33 of the fetuses (40.2%), more frequently in cases without associated intracardiac defects (56.8%). Trisomy 21 occurred in just over one quarter the series, and in 43.2% of cases without associated defects. In addition, 11% of fetuses had trisomy 18, and one had trisomy 13. Extracardiac anomalies were present in 12 of the fetuses (14.6%), more frequently in cases without associated abnormalities. Of fetuses with more complex defects, 46.4% had hypoplasia of the left ventricle and aorta. Complete atrioventricular block was present in 10 of the fetuses (12.2%), mainly in fetuses with other malformations, and particularly with left isomerism. Recurrence of congenital heart disease was observed in 5 of the fetuses (6.1%). Outcome: In 25 instances (30.5%) the parents opted for termination of pregnancy. Of 57 cases that continued through pregnancy, 9 fetuses died prior to term (15.8%), 32 died postnatally (56.13%) and only 16 fetuses (28.1%) survived. Overall, the mortality was higher in cases with associated malformations, in those with heart failure or those with atrioventricular block. Cardiac surgery was performed in 19 infants, with 5 dying postoperatively, and one late. Conclusions: Our data show a high prevalence of atrioventricular septal defect associated with other malformations when diagnosed during fetal life. This combination is less frequently associated with chromosomal and extracardiac anomalies, but more often with obstructive lesions of the left heart and with atrioventricular block. The association results in a less favourable outcome.