Lantibiotics are a diverse family of bacterially synthesized antimicrobial peptides produced by gram-positive bacteria. They usually have a broad spectrum of targets, often including closely related strains. The production of lantibiotics must thus be coupled with a mechanism by which the producing strain can protect itself from the lethal action of its own antimicrobial compound. This mechanism is referred to as immunity. Lantibiotic immunity is usually provided by one, or both, of two methods i.e. by a specific immunity peptide (designated LanI) and/or a specialised ABC transporter system (designated LanFE(G)). Significantly, although the specific immunity peptides function in a similar manner, there is very little homology between them. This is reflected in the specific nature of the immunity provided. Finally, of equal importance is the manner in which these immunity determinants are regulated such that their expression is timed to occur with, or immediately prior to, lantibiotic production to ensure successful self-protection.