The endocervix plays an important role in providing appropriate protective mechanisms of the upper female reproductive tract (FRT) while at the same time providing the appropriate milieu for sperm transport. Hormone fluctuations throughout the menstrual cycle contribute to changes in the mucosal environment that render the FRT vulnerable to infectious diseases. The objective of this study was to identify genes in human endocervix tissues that were differentially expressed in the follicular versus the luteal phases of the menstrual cycle using gene expression profiling. A microarray using the IIlumina platform was performed with eight endocervix tissues from follicular and four tissues from luteal phases of the menstrual cycle. Data analysis revealed significant differential expression of 110 genes between the two phases, with a P value <0.05 and a fold change cutoff of 1.5. Categorization of these genes, using Ingenuity Pathway Analysis, MetaCore from Thomson Reuters, and DAVID, revealed genes associated with extracellular matrix remodeling and cell-matrix interactions, amino acid metabolism, and lipid metabolism, as well as immune regulation in the follicular phase tissues. In luteal phase tissues, genes associated with chromatin remodeling, inflammation, angiogenesis, oxidative stress, and immune cell regulation were predominately expressed. Using samples from additional patients' tissues, select genes were confirmed by quantitative real-time PCR; immunohistochemical staining was also done to examine protein levels. This is the first microarray analysis comparing gene expression in endocervix tissues in cycling women. This study identified key genes and molecular pathways that were differentially regulated during the menstrual cycle.