The Ribosomal Database Project (RDP-II) is a curated database offering ribosomal RNA (rRNA) nucleotide sequence data in aligned and unaligned forms, along with analysis services and associated computer programs. Hosted by the Center for Microbial Ecology at Michigan State University, RDP-II has updated its data alignments to include over 9700 small subunit rRNA sequences. The recent development of an ObjectStore database aims to enhance data updating speed, accuracy, and user access. RDP-II provides phylogenetically ordered alignments, derived phylogenetic trees, tRNA secondary structure diagrams, and various software programs for handling, analyzing, and displaying alignments and trees. The data are available via anonymous FTP and the World Wide Web (http://www.cme.msu.edu/RDP). The RDP-II team plans to incorporate new data into the ObjectStore DBMS and improve tools for producing phylogenetic trees, while also establishing connections with Bergey's Manual of Systematic Bacteriology.The Ribosomal Database Project (RDP-II) is a curated database offering ribosomal RNA (rRNA) nucleotide sequence data in aligned and unaligned forms, along with analysis services and associated computer programs. Hosted by the Center for Microbial Ecology at Michigan State University, RDP-II has updated its data alignments to include over 9700 small subunit rRNA sequences. The recent development of an ObjectStore database aims to enhance data updating speed, accuracy, and user access. RDP-II provides phylogenetically ordered alignments, derived phylogenetic trees, tRNA secondary structure diagrams, and various software programs for handling, analyzing, and displaying alignments and trees. The data are available via anonymous FTP and the World Wide Web (http://www.cme.msu.edu/RDP). The RDP-II team plans to incorporate new data into the ObjectStore DBMS and improve tools for producing phylogenetic trees, while also establishing connections with Bergey's Manual of Systematic Bacteriology.