Nucleotide and protein sequence databases are major resources for biological and medical research. This chapter introduces the European Molecular Biology Laboratory (EMBL) Nucleotide Sequence Database, a comprehensive primary data archive for nucleic acid sequences, and Genome Reviews, a secondary database that provides an up-to-date, standardized and comprehensively annotated view of the genomic sequence of selected organisms with completely deciphered genomes. Focusing on plant nucleotide sequences, we demonstrate how these data are accessed, how sequence similarity searches are performed and how we can obtain a wealth of additional information relating to genome sequences using Integr8.