A systematic and comprehensive database for copy number variations and related diseases, in which all the records were manually extracted from experimental data published in CNV-related articles. Hence, CNVD database is a reliable and comprehensive resource for studying diseases associated copy number variations. Users can search the database in several ways: by gene name, disease name, chromosome location, or copy number variation region. In query results, each record contains such information: species, chromosomes, the start and end locations of the CNV, related disease, genes in the CNV region and PubMed ID of the source article. The results can be downloaded in batches or single, according to the users' need.