SILVA the rRNA Gene Databases

SILVA ( represents the world's leading public database for ribosomal RNA (rRNA) gene sequences and provides comprehensive, quality checked, and regularly updated data sets of aligned small (16S/18S, SSU) and large subunit (23S/28S, LSU) sequences for all three domains of life (Bacteria, Archaea, and Eukarya).

The service also includes an integrated and constantly maintained microbial taxonomy, representing the current reference in environmental microbiology.

The SILVA project is located within the public scientific sector and actively assisted by Ribocon (maintenance and advancement of the databases) as part of a public-private-partnership. See page on our Networking activities for more information.

The SILVA web portal offers different entry points to access the integrated database content. Browse and comprehensive search functions allow to view sequence metadata and quality information, and to obtain further information from linked external resources.

Selected database entries can be collected within a cart system and downloaded in various formats for further local use. Also the complete database content as well as the SILVA taxonomy can be retrieved in different formats.

The SILVA database is organized in different layers of increasing sequence quality (Parc, Ref/Ref NR) and selected layers are also offered as database files for direct local access and usage by the ARB software package. All sequences offered by SILVA are aligned according to the high-quality ARB/SILVA global alignment which is maintained since more than 30 years.

Besides database access and data retrieval options, SILVA offers a number of free online data processing and analysis functions such as sequence alignment and classification, probe and primer evaluation, as well as SILVAngs, a highly user-friendly amplicon data set (NGS) analysis service. The SILVA portfolio is completed by different complementary projects such as the unification of the Eukaryotic microbial taxonomy (UniEuk).

In case you have specific SILVA requirements which are not satisfied by the downloads and services provided at and which demand for Commercial Premium Support, please feel free to contact us anytime with a short description of your needs in order to explore your options and corresponding costs.

Examples for such support range from customized database exports to consulting on your specific workflow, as well as data analysis services including supervised sequence classification/identification, phylogenetic reconstruction, and probe/primer evaluation.

Additional customised SILVA-related support and services are offered by Ribocon on request:

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Core Data Resource

They represent a set of European data resources of fundamental importance to the wider life-science community and the long-term preservation of biological data. Read more ...

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SILVA Database Status

Current Release:

SILVA 138.1 (August 2020)
Detailed release information

# of sequences:

SSU Parc: 9.469.124 (+3.395.943)
SSU Ref: 2.224.740 (+134.072)
SSU Ref NR: 510.508 (-184.663)

The term Parc represents the complete SILVA SSU database content.
Ref and Ref NR represent improved subsets for which also corresponding ARB downloads are provided (with a guide tree only included for Ref NR).

License Information

With the latest SILVA release 138, the project has resigned its original dual licensing model:

The databases are now based on a Create Commons Attribution 4.0 (CC-BY 4.0) license and are fully free also for non-academic users.

See SILVA Terms of Use/License Information