Background: Ultrasonography can measure a variety of fetal factors, which have been linked to gestational age. It has become the most common way to check on a fetus's health. The fetal biparietal diameter (BPD), abdominal circumference, transcerebellar diameter (TCD), and femur length (FL) are the most common biometric markers used to evaluate fetal growth. Aim: Detection of the accurate gestational age evaluation method in second half of pregnancy comparing TCD and conventional fetal biometry. Materials and methods: This cross-sectional observational study was carried out on 294 pregnant women in their second half of pregnancy at the Department of Obstetrics and Gynecology, Port Said University Maternity Hospital and Diarb Negm Hospital. Results: TCD was accurate in 91.5% of the cases. While the FL was accurate in 83% of the cases.The BPD was accurate in 80 % of the cases and by combination of TCD and FL the accuracy of G.A estimation was 95.9%.