The Plant Male Reproduction Database (PMRD) is a comprehensive resource for browsing and retrieving knowledge about genes and mutants related to plant male reproduction. Currently, PMRD holds information for 4353 genes and 343 mutants related with plant male reproduction in 33 plant species. The database provides curated annotations and the genomic information, including gene full names, gene symbols, locations, sequences, gene function summaries, results of gene expression assays, mutant phenotypes, male sterility categories, and related publications.