Research in plant pathology is changing dramatically. Genomic and post-genomic investigations are generating large datasets, which allow the formation of holistic and predictive investigations of both pathogens and their plant hosts. The genomes of plant pathogenic bacteria are relatively easy to sequence, thus leading to further investigations on gene expression, proteomics and metabolomics. One of the emerging models for studying bacterial pathogenesis is Pseudomonas syringae pv. tomato strain DC3000 (Pst DC3000). This review will focus on the use of ‘post-genomic’ tools that provide insight into the interaction of Pst DC3000 with its various plant hosts.