Background: Ultrasound measurement of biparietal diameter “BPD", head circumference “HC", abdominal circumference “AC" and femur length “FL" can accurately detect gestational age “GA" in normal pregnancies. The study aims to assess the accuracy of transcerebellar diameter “TCD" in estimating the GA in normal and intra-uterine growth restriction “IUGR" pregnancies.   
Methods: A cross-sectional study was carried out on 30 pregnant women with normal pregnancy (group A) and 30 pregnant women with IUGR (group B). Ultrasound measurement of fetal biometry was done, including the following parameters: BPD, HC, AC, FL and TCD.  
Results: Regression analysis for GA by date using different measures among the normal group showed that TCD had the highest determination (0.886), which increased to 0.958 when TCD was combined with FL and AC. On the other hand, regression analysis for GA by date among the IUGR group showed that TCD had the highest determination (0.988), which increased to 0.990 when TCD was combined with BPD.  
Conclusion: Fetal TCD is a more reliable method in the 3rd trimester of gestation to determine the GA than BPD and other biometric measures, especially in IUGR pregnancies.