The Gene Expression Omnibus (GEO) repository at the National Center for Biotechnology Information (NCBI) archives and disseminates microarray and other high-throughput data. The database supports MIAME-compliant data submissions, capturing fully annotated raw and processed data. GEO offers multiple data deposit options, including web forms, spreadsheets, XML, and Simple Omnibus Format in Text (SOFT). It provides user-friendly web-based interfaces and applications to help users explore, visualize, and download the vast amount of data stored in GEO. As of September 2006, GEO holds over 120,000 samples, representing 3.2 billion individual measurements from more than 2000 laboratories worldwide. The database is designed to efficiently handle diverse and complex data formats, with a flexible structure that can accommodate various data styles. GEO also offers tools for data retrieval, exploration, and visualization, including Entrez search capabilities, profile charts, and hierarchical cluster heat maps. These features enable researchers to quickly locate, analyze, and interpret relevant data. Future plans include enhancing data retrieval and mining features, improving user experience, and expanding the types of data supported.The Gene Expression Omnibus (GEO) repository at the National Center for Biotechnology Information (NCBI) archives and disseminates microarray and other high-throughput data. The database supports MIAME-compliant data submissions, capturing fully annotated raw and processed data. GEO offers multiple data deposit options, including web forms, spreadsheets, XML, and Simple Omnibus Format in Text (SOFT). It provides user-friendly web-based interfaces and applications to help users explore, visualize, and download the vast amount of data stored in GEO. As of September 2006, GEO holds over 120,000 samples, representing 3.2 billion individual measurements from more than 2000 laboratories worldwide. The database is designed to efficiently handle diverse and complex data formats, with a flexible structure that can accommodate various data styles. GEO also offers tools for data retrieval, exploration, and visualization, including Entrez search capabilities, profile charts, and hierarchical cluster heat maps. These features enable researchers to quickly locate, analyze, and interpret relevant data. Future plans include enhancing data retrieval and mining features, improving user experience, and expanding the types of data supported.