Objective: The correlation between cerebro-umbilical pulsitility indices and high risk pregnancy. Subjects: The study was included 40patients, 20 preeclampsia patients, 20 gestational diabetes patients. Methods: All patients in the study underwent ultrasound assessment that includes fetal biometry, fetal weight, a four component biophysical profile score and Doppler ultrasound studies of umbilical artery (UA) and middle cerebral artery ( MCA). Results: The study was included 40 patients with high risk pregnancy. They were classified into 2 groups according to the risk pre-eclampsia group and diabetic group whether the two groups are equal in number being 20 per each.UA-PI is significant higher in pre-eclampsia group than diabetic group as well as MCA-PI and C/U ratio is significantly lower in pre-eclampsia group than diabetic group . Conclusion: Doppler investigation of the cerebro – umbilical pulsitlity indices and ratio play an important role in monitoring high risk pregnancies complicated by placental vascular insufficiency and fetal growth restriction (FGR). In a relatively well controlled diabetic pregnancies not complicated by preeclampsia or FGR the values of color Doppler indices are similar to normal pregnancy