Peptidoglycan hydrolases or autolysins are enzymes capable of cleaving covalent bonds in bacterial peptidoglycan cell wall layer. They can participate in the cell division process, in the release of turnover products from peptidoglycan during cell growth, and in cell autolysis induced under particular conditions. The protocol for zymogram presented below should enable the identification of such enzymes through their separation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis containing bacterial cells as substrate.