We have undertaken a comprehensive gene expression profiling of the entire process of murine lung development using oligonucleotide-based microarrays. Our data reveals the expression pattern of approximately 11,000 genes throughout the morphologic stages of lung development. This includes known genes with unappreciated pulmonary expression and novel genes with undefined functions. Traditional gene expression analysis techniques verify a high degree of confidence in the microarray data. Examination of the data confirms previously known patterns of expression for extracellular matrix genes and provides new information regarding relationships in temporal expression among groups of these genes. Large-scale cluster analysis reveals associations in the expression profile of specific genes with defined developmental processes. For instance, we identify groups of genes, which are coordinately expressed with extracellular matrix genes during lung development. These data should serve as a resource for the pulmonary research community and assist in deciphering the molecular mechanisms governing normal lung development as well as those involved in aberrant developmental pathology.