The miRBase database is a comprehensive resource for microRNA (miRNA) sequence data, annotation, and predicted gene targets. It serves three main roles: the miRBase Registry, which assigns names to novel miRNA sequences before their publication; miRBase Sequences, the primary repository for miRNA sequence data and annotation; and miRBase Targets, a database of predicted miRNA target genes. The registry ensures consistent nomenclature, while the sequences database provides detailed information on miRNA structures and functions. The targets database uses an automated pipeline to predict miRNA binding sites in 3′-untranslated regions (3′-UTRs) of mRNA sequences, offering high-quality predictions with statistical significance. miRBase is freely available online at http://microrna.sanger.ac.uk/ and supports various formats for data download and integration.The miRBase database is a comprehensive resource for microRNA (miRNA) sequence data, annotation, and predicted gene targets. It serves three main roles: the miRBase Registry, which assigns names to novel miRNA sequences before their publication; miRBase Sequences, the primary repository for miRNA sequence data and annotation; and miRBase Targets, a database of predicted miRNA target genes. The registry ensures consistent nomenclature, while the sequences database provides detailed information on miRNA structures and functions. The targets database uses an automated pipeline to predict miRNA binding sites in 3′-untranslated regions (3′-UTRs) of mRNA sequences, offering high-quality predictions with statistical significance. miRBase is freely available online at http://microrna.sanger.ac.uk/ and supports various formats for data download and integration.