Prenatal diagnosis of the DiGeorge/velo-cardio-facial syndrome has become possible since it was recognized that this syndrome is caused by a submicroscopic deletion in chromosome 22q11. In a sporadic patient presenting a conotruncal heart defect and polyhydramnios, the del 22q11 was made prenatally by fluorescence in situ hybridization (FISH) after amniocentesis. Seven additional patients with a del 22q11 were identified, who presented during pregnancy with polyhydramnios. In one of them, unilateral hydronephrosis was present. These findings further add to a growing list of clinical presentations of a del 22q11 and suggest that in patients with polyhydramnios and a conotruncal heart defect or uropathy, fetal karyotyping should be complemented by FISH for a del 22q11.