BACKGROUND\nMaternal diabetes is associated with numerous adverse effects in fetal and neonatal organs, including the lungs.\nOBJECTIVE\nTo investigate the effects of intrauterine hyperglycemia on neonatal lung biological signaling, we performed a microarray analysis in the lungs of four 14-day-old rat pups born to a hyperglycemic dam and in four age mate control pup lungs.\nMETHODS\nTotal RNA was isolated and cDNA was hybridized to the Illumina Sentrix® RatRef-12 BeadChip. A total of 22,000 genes were analyzed for expression profiles and functional gene clustering. Ten selected genes differentially expressed in microarray were additionally analyzed by the real-time polymerase chain reaction.\nRESULTS\nTwo hundred twenty-seven genes were differentially expressed in neonatal rat lungs exposed to intrauterine hyperglycemia when compared to normoglycemic controls (fold change > 1.2, p < 0.001). Functional clustering analysis revealed increased expression in signaling pathways involved with extracellular matrix regulation. The most significantly downregulated functions were cell proliferation, extracellular region, cell adhesion and reactive oxygen species metabolism.\nCONCLUSION\nWe found significant hyperglycemia-induced gene expression alterations in neonatal rat pulmonary tissue which may interfere with lung growth and biological signaling pathways.