The Bacterial Isolate Genome Sequence Database (BIGSdb) is a scalable, web-accessible database system designed to store and analyse linked phenotypic and genotypic information in a computationally efficient manner. Sequence data can range from single sequence reads to multiple contigs generated by whole genome sequencing technologies. The system incorporates the capacity to define and identify any number of loci and genetic variants at those loci within the stored nucleotide sequences. These loci can be further organised into schemes for isolate characterisation or for evolutionary or functional analyses. See Jolley and Maiden 2010, BMC Bioinformatics 11:595 (http://www.biomedcentral.com/1471-2105/11/595).