We describe two infants of diabetic mothers (IDMs) with branchial arch, vertebral, cardiovascular, and central nervous system malformations. Our observations support the hypothesis of Grix et al [1982] that branchial arch abnormalities may occur with increased frequency in children of diabetic mothers. Two other IDMs (a literature case with hemifacial microsomia and caudal regression, and a child we evaluated with ear abnormalities and the femoral hypoplasia-unusual facies syndrome) reinforce this suggested association. The latter two patients also demonstrate concurrence of branchial arch abnormalities with caudal regression and/or femoral hypoplasia, field defects known to be strongly associated with maternal diabetes mellitus. Genetic counseling for maternal diabetes mellitus probably should include information regarding all of these developmental abnormalities.