Sirenomelia is a very rare congenital developmental disorder of the lower extremities, and all the other derivatives from the caudal mesoderm, mainly the viscera i.e. kidneys, gonads and hindgut. In the majority of cases, it is incompatible with life in the neonatal period as it is associated with renal agenesis. The importance of detecting this anomaly in the first trimester lies in this lethality in order to offer the option of termination of pregnancy at an earlier gestation. Appropriate counselling at diagnosis is essential to give the couple a clear picture of what they might expect postnatally regarding the renal anomalies or the many surgeries which might be required for the lower limbs and viscera. We present a case series (n = 5) diagnosed by ultrasound at our center between January 2014-2020. Through this brief article, we aim to give a key to the antenatal diagnosis of this rare anomaly, an aid on how not to miss it and its subsequent management.