The Notch/Notch-ligand pathway is a pathway that regulates cell fate decisions and patterning in various tissues. Several components of this pathway are expressed in the developing lung suggesting that this pathway is important for cellular patterning of the airways. Fringe proteins, which modulate Notch signaling, are crucial for defining morphogenic borders in a variety of organs. Their role in controlling cellular differentiation along anterior-posterior axis of the airways is unknown. Herein, we report the temporal-spatial expression patterns of Lunatic fringe (Lfng) and Notch-regulated basic helix-loop-helix factors, Hes1 and Mash-1, during murine lung development. Lfng was only expressed during early development in epithelial cells lining the larger airways. Those epithelial cells also expressed Hes1, but at later gestation Hes1 expression was confined to epithelial cells lining the terminal bronchioles. Mash-1 displayed a very characteristic expression pattern. It followed neural crest migration in the early lung while at later stages Mash-1 was expressed in the neuroendocrine cells of the lung. To clarify whether Lfng influences airway cell differentiation Lfng was overexpressed in distal epithelial cells of the developing mouse lung. Overexpression of Lfng did not affect the spatial and temporal expression of Hes1 and Mash-1. Neuroendocrine cGRP and Pgp9.5 expression was not altered by Lfng overexpression. Expression of proximal ciliated (-tubulin IV), non-ciliated (CCSP) and distal epithelial cell (SP-C, T1) markers also was not influenced by excess of Lfng. Overexpression of Lfng had no effect on mesenchymal cell marker (-sma, vWF, Pecam-1) expression. Collectively, the data suggest that Lunatic fringe does not play a significant role in determining cell fate in fetal airway epithelium.