Current activities and future prospects for the biotechnology of lactic acid bacteria arc reviewed. Genetic engineering technology, inchiding advances and limitations of plasmid vectors and chromosomal integration strategies are discussed together with the status of gene expression and the importance of in vivo gene transfer systems and transposition. Areas of biotechnological application considered include proteolysis and flavour generation, bacteriophages and bacteriophage resistance, anlimicrobials, metabolic engineering and the possible uses of lactic acid bacteria in relation to health.