Background: A great effort has been made to predict fetal lung maturity to determine when a fetus is likely to develop neo-natal complications. The fetal pulmonary artery Doppler velocimetry may be useful to predict FLM. The aim of this work was to predict Lung maturity with fetal breathing movements and Pulmonary artery Doppler indices, the outcome measures will be correlated with respiratory distress syndrome (RDS) and admission in neonate intensive care unit. Methods: This cross-sectional study was carried out on 66 pregnant women had a singleton pregnancy with gestational ages from 34-36 weeks admitted in the unit for inevitable preterm labour. Neonates were further subdivided in to two groups regarding RDS: Group I without RDS included 42 cases and Group II with RDS included 16 cases. All patients were subjected to clinical examination, Spectral Doppler ultrasound was used to obtain fetal main pulmonary artery waveforms, fetal biometry. Results: It was found that there was a significant positive correlation between HC and BPD, AC and HC, PSV and FL, S/D and BPD, PI and BPD, RI and HC, AT/ET and FL, and AT/ET and PSV. And there was significant negative correlation between FL and BPD, PSV and BPD, PSV and HC, PI and PSV, AT/ET and BPD, AT/ET and HC, and AT/ET and PI. PI, RI, PSV, AT/ET, BPD, HC and FL were significant predictors for the fetal lung maturity. Conclusions: Ultrasound evaluation of Fetal Mean Pulmonary Artery Doppler can be used as a rapid non-invasive accurate method for prediction of fetal lung maturity and neonatal respiratory distress syndrome, PI, RI, PSV, AT/ET, BPD, HC and FL can be used for prediction of fetal lung maturity