The noncoding RNAs and protein related biomacromolecules interaction database (NPInter; http:// bioinfo.ibp.ac.cn/NPInter or http://www.bioinfo.org. cn/NPInter) is a database that documents experimentally determined functional interactions between noncoding RNAs (ncRNAs) and protein related biomacromolecules (PRMs) (proteins, mRNAs or genomic DNAs). NPInterintends to provide thescientific community with a comprehensive and integrated tool for efficient browsing and extraction of information on interactions between ncRNAs and PRMs. Beyond cataloguing details of these interactions, the NPInter will be useful for understanding ncRNA function, as it adds a very important functional element,ncRNAs,tothebiomoleculeinteractionnetwork and sets up a bridge between the coding and the noncoding kingdoms.