Rfam is a curated database of non-coding RNA families, each represented by multiple sequence alignments, consensus secondary structures and covariance models. Our families may be divided into non-coding RNA genes, structured cis-regulatory elements and self-splicing RNAs. Rfam families are created from ENA sequence data and experimental evidence in the literature. Rfam provides ontology terms and external references, as well as search tools to enable users to query their sequence against Rfam data. Rfam is used for automatic annotation of genome sequences as well as a test dataset for many RNA bioinformatics methods.