The Ribosomal Database Project (RDP) is a curated database that provides ribosome-related data, analysis services, and associated computer programs. The RDP offers phylogenetically ordered alignments of ribosomal RNA (rRNA) sequences, derived phylogenetic trees, rRNA secondary structure diagrams, and various software for handling, analyzing, and displaying alignments and trees. Data are available via anonymous FTP, electronic mail, and gopher. The RDP includes rRNA sequences from Archaea, Bacteria, and Eucarya, with detailed annotations and updates. The electronic mail server provides services such as ribosomal probe checking, approximate phylogenetic placement, and automated alignment. New features include improved analysis options, a new SUGGEST_TREE command, and the addition of new programs like DNArates and data conversion tools. Future plans include making unaligned rRNA sequences available, implementing a full web interface, developing an alignment editor, and enhancing existing services. The RDP is supported by the National Science Foundation and contributions from various researchers and organizations.The Ribosomal Database Project (RDP) is a curated database that provides ribosome-related data, analysis services, and associated computer programs. The RDP offers phylogenetically ordered alignments of ribosomal RNA (rRNA) sequences, derived phylogenetic trees, rRNA secondary structure diagrams, and various software for handling, analyzing, and displaying alignments and trees. Data are available via anonymous FTP, electronic mail, and gopher. The RDP includes rRNA sequences from Archaea, Bacteria, and Eucarya, with detailed annotations and updates. The electronic mail server provides services such as ribosomal probe checking, approximate phylogenetic placement, and automated alignment. New features include improved analysis options, a new SUGGEST_TREE command, and the addition of new programs like DNArates and data conversion tools. Future plans include making unaligned rRNA sequences available, implementing a full web interface, developing an alignment editor, and enhancing existing services. The RDP is supported by the National Science Foundation and contributions from various researchers and organizations.