Tracheal aspirates were isolated from 121 preterm neonates during the firstWeek of life to isolate mesenchymal stem cells (MSCs) and Transforming growthFactor 1 (TGF-B) assay to correlate them with the development of Bronchopulmonary dysplasta.The median number of colonis of MSCs in the BPD group was significantlyHigher than those without BPD with a p value 0.011 and the median number of Vlusters of NSCs in the BPD group was significantly higher than than those without BPDWith a p value 0.003.The median of TGF-B1 was significantly higher in the BPD group with a p value 0.021.