Bacteriocins produced by lactic acid bacteria are a heterogeneous group of peptide inhibitors. Most of bacteriocins have relatively narrow inhibitory spectra. A few of them have wider inhibitory spectra, being active against a wide range of gram-positive bacteria. Bacteriocins can be divided into three types. There are small heat-stable peptides, large heat-labile proteins, and lantibiotics. Their physico-chemical nature, genetic behavior and application are reviewed.