A comprehensive Arabidopsis genomic resource has been developed at the Nottingham Arabidopsis Stock Centre (NASC) to support the international plant community. This browser, termed AtEnsembl, provides a detailed and user-friendly interface for accessing a wide range of Arabidopsis-based genomic information and post-genomic resources using the Ensembl browser. The resource aims to provide the broadest possible range of Ensembl features, including pointers to germplasm as well as representations of gene and protein information, links to Affymetrix gene expression data, and extensive data download capabilities.