Background: Assessment of fetal weight is a vital and universal part of antenatal care, not only in the management of labor and delivery but often during the management of high risk pregnancies and growth monitoring. The common methods to estimate fetal birth weight are clinical and sonographic estimation with a wide range of accuracy. Objective: To correlate fetal abdominal subcutaneous tissue thickness (FASTT) measured by abdominal ultrasound at term and birth weight measured immediately after delivery and to obtain a cut-off value of FASTT to predict large and small for gestational age babies in our population at Alsayed Galal Hospital and Damanhur medical national institute (D.M.N.I). Patients and methods: This prospective observational study was carried out at Alsayed Galal Hospital and Damanhur medical national institute (D.M.N.I).A total of 200 pregnant women at term admitted to the labor ward for delivery at Alsayed Galal Hospital and D.M.N.I. between June 2019 and March 2020. Results: Of the 200 neonates of the included women, 148 (74.0%) had birth weight (2500-4000) g 14 (7.0%) had birth weight<2500g, while 38 (19.0%) had birth weight>4000 g. There was a significant positive correlation between fetal anterior abdominal wall fat thickness and birth weight. FAST was a significant predictor of Birth weight > 4000 g, as indicated by the significant large area under the curve (AUC). Conclusion: FASTT is a good indicator of birth weight. It is a better parameter for LGA than SGA. It showed a high statistically significant correlation with AC. Yet, it is less accurate than AC as an indicator of fetal macrosomia. FASTT is not affected by fetal gender and has no direct relation to the mode of delivery.      FAST can be combined with weight estimation formulas as a method to increase its accuracy especially at birth weight extremities. However, a large study conducted on a wider scale of Egyptian population should be done in attempt to generate formulas for the estimation of fetal weight based on the Egyptian ethnic group and be the reference of medical practice in Egypt.