GeneCards Version 3 is a comprehensive, authoritative compendium of human gene information, integrating data from over 80 sources. It provides a web-based card for each of more than 73,000 human genes, covering categories such as protein coding, pseudogene, RNA gene, genetic locus, cluster, and uncategorized. Version 3 introduces a faster and more sophisticated search engine, a revamped infrastructure, and enhanced features for gene-set analysis. Key features include GeneALaCart for batch queries, GeneDecks for identifying similar genes with shared annotations, and a new Inferred Functionality Score (GIFtS) tool for assessing gene functionality. The database now includes expanded visualization of gene expression patterns, integrated alternative splicing patterns, and enhanced sections for SNPs and pathways. It also provides direct links to research reagents and gene-related drugs. The new search engine efficiently handles complex queries, with results returned in milliseconds. The GeneCards webcard has been significantly enhanced, with detailed sections on proteins, gene function, pathways, drugs, transcripts, and SNPs. The database architecture supports a relational model with 84 entities and 28 relationships, enabling efficient querying and analysis. The system includes a quality assurance tool, GeneQArds, for validating data integrity and search results. GeneCards has been used in various collaborative projects, including SYNLET and SysKid, for systems biology and disease research. The new version offers improved performance, expanded functionality, and enhanced data integration, making it a valuable resource for biomedical research.GeneCards Version 3 is a comprehensive, authoritative compendium of human gene information, integrating data from over 80 sources. It provides a web-based card for each of more than 73,000 human genes, covering categories such as protein coding, pseudogene, RNA gene, genetic locus, cluster, and uncategorized. Version 3 introduces a faster and more sophisticated search engine, a revamped infrastructure, and enhanced features for gene-set analysis. Key features include GeneALaCart for batch queries, GeneDecks for identifying similar genes with shared annotations, and a new Inferred Functionality Score (GIFtS) tool for assessing gene functionality. The database now includes expanded visualization of gene expression patterns, integrated alternative splicing patterns, and enhanced sections for SNPs and pathways. It also provides direct links to research reagents and gene-related drugs. The new search engine efficiently handles complex queries, with results returned in milliseconds. The GeneCards webcard has been significantly enhanced, with detailed sections on proteins, gene function, pathways, drugs, transcripts, and SNPs. The database architecture supports a relational model with 84 entities and 28 relationships, enabling efficient querying and analysis. The system includes a quality assurance tool, GeneQArds, for validating data integrity and search results. GeneCards has been used in various collaborative projects, including SYNLET and SysKid, for systems biology and disease research. The new version offers improved performance, expanded functionality, and enhanced data integration, making it a valuable resource for biomedical research.