| In the post-genomic era, genomics and proteomics data generated from high-throughput technology are accumulated quickly. The biology community needs powerful tools to analyze large size gene and protein sets conveniently. Moreover, researchers want to understand biologic meaning of interested genes and proteins. Software that provides biologists with large-scale genes and proteins annotation capabilities is in a high demand. To meet this trend, we have established a web server called iGepros, which presents strong annotation power for large size gene and protein sets. At the meantime, the server is user-friendly and some demos are offered on-line, which make it suitable for a wide range of users even those with little or none programming experience. In addition, the iGepros server provides operations to connect genes and proteins, which allows users to compare different omics data sets.