miRWalk is an open-source online resource for predicting microRNA (miRNA) binding sites in human, mouse, rat, dog, and cow genes. The platform uses a random-forest-based algorithm called TarPmiR to predict miRNA target sites across the entire transcript sequence, including 5'-UTR, CDS, and 3'-UTR. It integrates results from multiple databases, including TargetScan, miRDB, and miRTarBase, to provide accurate and validated miRNA-target interactions. The database is built using Python, MySQL, and HTML/Javascript, and is available at http://mirwalk.umm.uni-heidelberg.de. miRWalk features a modular design, allowing for easy updates and extensions. It enables users to search for miRNA or gene targets, and provides various filtering options to refine results. The system supports exporting data in CSV format and visualizing miRNA-target interactions using D3.js. The database is updated twice a year, ensuring up-to-date information on miRNA-target interactions. The platform allows users to search for single or multiple miRNAs and genes, and provides results including miRNA IDs, gene IDs, scores, and comparisons with other algorithms like miRDB or TargetScan. Users can also perform gene set enrichment analysis (GSEA) to identify significant functional groups among target genes. miRWalk offers a user-friendly interface for quickly accessing, analyzing, and visualizing miRNA-target interactions. The database is continuously updated and improved, making it a valuable resource for researchers studying miRNA functions and their roles in biological processes. The system is freely available and supports a wide range of applications in genomics and molecular biology.miRWalk is an open-source online resource for predicting microRNA (miRNA) binding sites in human, mouse, rat, dog, and cow genes. The platform uses a random-forest-based algorithm called TarPmiR to predict miRNA target sites across the entire transcript sequence, including 5'-UTR, CDS, and 3'-UTR. It integrates results from multiple databases, including TargetScan, miRDB, and miRTarBase, to provide accurate and validated miRNA-target interactions. The database is built using Python, MySQL, and HTML/Javascript, and is available at http://mirwalk.umm.uni-heidelberg.de. miRWalk features a modular design, allowing for easy updates and extensions. It enables users to search for miRNA or gene targets, and provides various filtering options to refine results. The system supports exporting data in CSV format and visualizing miRNA-target interactions using D3.js. The database is updated twice a year, ensuring up-to-date information on miRNA-target interactions. The platform allows users to search for single or multiple miRNAs and genes, and provides results including miRNA IDs, gene IDs, scores, and comparisons with other algorithms like miRDB or TargetScan. Users can also perform gene set enrichment analysis (GSEA) to identify significant functional groups among target genes. miRWalk offers a user-friendly interface for quickly accessing, analyzing, and visualizing miRNA-target interactions. The database is continuously updated and improved, making it a valuable resource for researchers studying miRNA functions and their roles in biological processes. The system is freely available and supports a wide range of applications in genomics and molecular biology.