Abstract Background: Respiratory distress syndrome is a major cause of neonatal mortality and morbidity. Lung maturity is important in high-risk pregnancies. The strongest predictor of lung maturity is gestational age and also, can be assed by ultrasonographic markers as epiphyseal osscification centers. Aim of Study: This study was to evaluate the distal femoral, proximal tibial and proximal humeral ossification centers as predictive tools of fetal lung maturity. Patients and Methods: This study was prospective com-parative study was carried out on 100 pregnant women attended Obstetric and Gynecological Clinic of Damanhour Teaching Hospital. All cases in this study will subjected to: (1) History taking; (2) Complete clinical examination; (3) Investigations. After approval of local ethics committee, all patients were informed well about the procedure and had an informed written consent before carrying the procedure. Data were analyzed using IBM SPSS software package version 20.0. Data were collected, tabled then analyzed were p-values 0.05 were considered significant. Results: Our results revealed non-significant difference between women regarding demographic data, signs and symp-toms, past-history. Ultrasonographic examination revealed significant reduction of respiratory distress with increased osscification centers number and Also, ICU admission decre-wased significantly with increased osscification centers number. In addition, occification centers number significantly increased with increased gestational age. Conclusion: This study can concluded that the size and appearance of the proximal humeral epiphysis will be helpful to determine the gestational age and viability of the fetus in normal as well as medico legal cases.