Introduction: The differential diagnosis of an abdominal cyst can be challenging, and an accurate diagnosis is crucial for optimal antenatal management. The aim of this study was to compare the ante- and postnatal diagnoses of cases with abdominal cyst and to determine the diagnostic accuracy of ultrasonography. Material and Methods: A database review was performed regarding the diagnosis of fetal abdominal cyst covering the period 2002–2009. Structural characteristics and localizations of the cysts in the abdomen were recorded. Ante- and postnatal diagnoses were classified into systems according to the origin of the cyst and were compared. Perinatal outcomes were obtained for all cases. Results: 71 cases with an abdominal cyst were identified. The mean gestational age at the time of diagnosis was 25 ± 5.1 weeks. In 9 cases, there were extra-fetal structural abnormalities, and in 5 cases a chromosomal abnormality was determined. Seven pregnancies were terminated. Overall spontaneous mortality was 11/64 (17%). In 12/64 cases (18%), the cyst resolved at birth. After birth, nearly half of the cases required surgical correction and of these, 20% died. Sensitivity, specificity and positive predictive value of ultrasonography in identifying the system of origin were 88.1, 95.7 and 92.0%, respectively, with a 4.1% false-positive rate. Conclusion: Incorporation of different disciplines in the counseling, management and postpartum follow-up is crucial. Postnatal physical examination of fetuses with an abdominal cyst will help to prevent unnecessary surgery.