OBJECTIVE Our purpose was to assess whether perinatal complications contribute to lower intellectual attainment in offspring of diabetic mothers, independent of antepartum metabolic disregulation. METHODS Subjects were 223 pregnant women and their singleton offspring. Eighty-nine women had pregestational diabetes mellitus, 99 had gestational diabetes mellitus, and 35 had normal gestational glucose metabolism. Perinatal complications were prospectively recorded on an examination checklist. The intelligence quotient of the child was assessed with the Bayley Scales of Infant Development at age 2 years and the Stanford-Binet Intelligence Scale at age 3 to 5 years. RESULTS No significant correlations emerged between either measure of child's intelligence quotient and any prevalent perinatal complication, after statistical correction for socioeconomic status, race or ethnic origin, patient group, and antepartum metabolic control. CONCLUSIONS Given prevailing practices in diabetes management and obstetric and neonatal care, the effects of prevalent perinatal complications on the intellectual development of offspring of diabetic mothers appear minimal.