The clinical features of a fetus with sirenomelia, limb reduction defects, cardiovascular malformation and renal agenesis are reported. The mother of the child suffers from insulin dependent diabetes. The limb, cardiac and renal abnormalities are well recognized sequelae of diabetic pregnancies. The association of sirenomelia and maternal diabetes is somewhat controversial. The link between caudal regression syndrome, sirenomelia and maternal diabetes will be discussed.