Background: The sonographic measurement of fetal biacromial diameter can be used easily as a predictive method for prevention of perinatal complications of macrosomia by early detection and management. Aim of work: The objective of our study was the prediction of fetal macrosomia to improve fetal and maternal outcome, as well as to assess the measured value of biacromial diameter by ultrasound and to comparing the accuracy of various formulas for macrosomia prediction at different thresholds. Patients and Methods: This study included 151 pregnant women at last trimester of pregnancy (30-40 weeks) with intact membranes, who were attended to the department for complete ultrasound examination. Results : The current study showed that there was a statistical significant difference in biacromial diameter between non macrosomic and macrosomic babies and there was significant positive correlation between biacromial diameter and both estimated fetal and neonatal birth weight. Conclusion: The ultrasound measurement of fetal biacromial diameter could be an accurate and simple method for prediction of fetal macrosomia at birth.