We report a case of congenital pancreatic cyst detected prenatally by ultrasound in a fetus with evidence for a diagnosis of Beckwith-Wiedemann syndrome (BWS). Neonatal hypoglycaemia was prevented. The cyst was managed by internal drainage. This is the second reported case of BWS associated with pancreatic cystic dysplasia and the first time that this association has been detected prenatally. Differential diagnosis of cystic abdominal lesions occurring in utero should take pancreatic cysts into consideration. This case suggests that pancreatic cysts should be included in the BWS phenotype.