Cardiac output and cerebral blood flow velocity in the anterior cerebral and internal carotid arteries were investigated in eight large-for-date infants of insulin-dependent diabetic mothers and 12 healthy term infants during the first four days of life using two-dimensional/pulsed Doppler ultrasound. Temporal mean flow velocity was used as an indicator of changes in cerebral blood flow. Six of the eight infants of diabetic mothers had ventricular septal hypertrophy with reduced cardiac outputs and stroke volumes. Mean flow velocity in both cerebral vessels showed a comparable pattern in both groups throughout the study period and was independent of mean arterial pressure, suggesting unaltered cerebral hemodynamics in the infants of diabetic mothers.