Autosomal dominant polycystic kidney disease (ADPKD) arises from mutations in the PKD1 and PKD2 genes. The Polycystic Kidney Disease Mutation Database (PKDB) is an internet-accessible relational database containing comprehensive information about germline and somatic disease-causing variants within these two genes, as well as polymorphisms and variants of indeterminate pathogenicity. The PKDB database structure incorporates an interface between these gene variant data and any associated patient clinical data. An initiative of the Polycystic Kidney Disease Foundation, PKDB is a publicly accessible database that aims to streamline the evaluation of PKD1 and PKD2 gene variants detected in samples from those with ADPKD, as well as to assist ongoing clinical and molecular research in the field. As the accurate reporting of nucleotide variants is essential for ensuring the quality of data within PKDB, a mutation checker has been mounted on the PKDB server allowing contributors to assess the accuracy of their PKD1 and PKD2 variant reports. Researchers and clinicians may submit their PKD1/PKD2 gene variants and any associated deidentified clinical data via standardized downloadable data entry forms accessible through the PKDB site. PKDB has been launched with the full details of PKD1 and PKD2 gene variant reports published in 73 peer-reviewed articles. Through a series of user,friendly advanced search facilities, users are able to query the database as required.