It is now more than 30 years since cases of antenatally detected multicystic dysplastic kidney (MCDK) were first reported in the literature. Before then, MCDK was regarded as a rare anomaly, which generally presented as an abdominal mass in the neonatal period. Nephrectomy was the standard form of management. Over the last three decades, however, it has become apparent that MCDK is, in fact, a relatively common renal anomaly, with a prevalence in the range of 1 in 2500 to 1 in 4000.1 , 2 It has also become clear that the majority of MCDKs are small and clinically undetectable and would probably have remained unrecognized throughout the individual’s lifetime if they had not been detected on antenatal ultrasonography. The weight of published evidence now supports a conservative approach in the majority of cases, with nephrectomy being reserved for specific indications.