Type IV transporters are produced by several bacterial pathogens such as Agrobacterium tumefaciens, Bordetella pertussis, Brucella spp., Bartonella henselae, Helicobacter pylori and Legionella pneumophila. These transporters are critical for the pathogenic process in that they export important virulence factors across the membranes of the bacteria. Although the virulence factors that are exported by these transporters can be either nucleic acid or protein, the general mechanism of transport appears to be similar for members of this family. Recent findings have shed light on the architecture of type IV transporters and the roles that these transporters play in pathogenesis.