miRBase is a comprehensive online repository for microRNA (miRNA) nomenclature, sequence data, annotation, and target prediction. The current release (10.0) includes 5071 miRNA loci from 58 species, representing 5922 distinct mature miRNA sequences, an increase of over 2000 sequences since the previous release. miRBase provides various tools to facilitate studies of miRNA genomics, including genomic coordinates, cluster analysis, and overlap with annotated transcripts. The database also offers graphical views of genomic features to predict the boundaries of primary transcripts. miRBase is available at http://microrna.sanger.ac.uk/ and supports non-commercial use under a Creative Commons Attribution license. The article discusses the nomenclature scheme, data updates, experimental support, and genomic tools provided by miRBase, highlighting its role in advancing research on miRNA function and regulation.miRBase is a comprehensive online repository for microRNA (miRNA) nomenclature, sequence data, annotation, and target prediction. The current release (10.0) includes 5071 miRNA loci from 58 species, representing 5922 distinct mature miRNA sequences, an increase of over 2000 sequences since the previous release. miRBase provides various tools to facilitate studies of miRNA genomics, including genomic coordinates, cluster analysis, and overlap with annotated transcripts. The database also offers graphical views of genomic features to predict the boundaries of primary transcripts. miRBase is available at http://microrna.sanger.ac.uk/ and supports non-commercial use under a Creative Commons Attribution license. The article discusses the nomenclature scheme, data updates, experimental support, and genomic tools provided by miRBase, highlighting its role in advancing research on miRNA function and regulation.