Background: Accurate estimation of the gestational age [GA] is crucial for the appropriate management of pregnancy. Inaccurate GA estimation is associated with adverse perinatal outcomes. Precise knowledge of the expected date of delivery has a vital role in the management of pregnancies. Amongst the several clinical measures employed to assess the GA, the date of the last normal menstrual period [LNMP] is acknowledged to relate best with the GA. However, this method may not be always reliable and can sometimes be misleading. Foetal Abdominal Circumference [AC] is one the important foetal parameters to be affected early in the process of impaired foetal growth. So, Trans cerebellar Diameter/Abdominal Circumference [TCD/AC] ratio has been found to be constant and a gestational age independent parameter to assess foetal growth and can be useful in predicting foetal growth restriction. The aim of the present study was to evaluate accuracy of fetal trans-cerebellar diameter and fetal trans-cerebellar diameter to abdominal circumference [TCD/AC] ratio in assessment of gestational age for the prediction of normal fetal growth and intrauterine growth restriction. Methods: This was a prospective case control study conducted at the Obstetrics and Gynecology Department, Benha University Hospital, Benha – Egypt on 300 pregnant women [Group A]: included healthy pregnant women with morphologically normal fetuses between 14-40 weeks of gestation who came for routine antenatal sonography, [Group B]: included patients of suspected IUGR clinically. Results: HC, AC, and TCD were significantly lower in IUGR compared to controls. Meanwhile TCD/AC was significantly higher in IUGR compared to controls. Conclusion: In IUGR fetuses, the fetal TCD was less affected than fetal HC suggesting preferential preservation of cerebellar growth relative to other cranial structures. The TCD/AC ratio was helpful in recognizing abnormal fetal growth. Even when the GA was uncertain since this ratio was gestational age independent