Aims: To characterize a bacteriocin-like factor from Bacillus licheniformis 26 L-10/3RA isolated from buffalo rumen. Methods and Results: The culture supernatant exhibited the antibacterial activity against a number of indicator organisms in a cut-well agar assay under anaerobic conditions. The inhibitory component was purified by following ammonium sulphate precipitation, gel filtration and ion exchange chromatography and confirmed to be a single peptide. A single band on tricine-sodium dodecyl sulphate-polyacrylamide gel electrophoresis confirmed that the peptide was purified to homogeneity and having an estimated molecular mass of approximately 1400 dalton. Complete amino acid sequence of the peptide yielded 12 amino acids from the N-terminal end (ISLEICXIFHDN). No homology with previously reported bacteriocins was observed and has been designated as Lichenin. Lichenin was found to be hydrophobic, sensitive to atmospheric oxygen, retained biological activity even after boiling for 10 min and was active over a pH range of 4.0-9.0., Conclusions: The Lichenin represents the first anaerobiosis specific expression of bacteriocin-like compound isolated from Bacillus licheniformis 26 L-10/3RA of buffalo rumen origin. Significance and Impact of the Study: Lichenin could be a potential candidate for manipulating the rumen function at molecular level intended for improving the productivity of the ruminant.