The stable L-form cells derived from Staphylococcus aureus 209P were examined for the presence of cell wall lytic enzymes. The enzyme preparations from cells and culture fluid of the parent strain lysed both Micrococcus lysodeikticus cells and S. aureus cells, whereas the enzyme preparations from the L-form lysed M. lysodeikticus cells but not S. aureus cells. Lipoteichoic acid, which has been reported to be a regulator of the lytic enzyme, inhibited both enzyme preparations from the parent strain and the L-form. However, the susceptibility of the enzyme preparation from the L-form to lipoteichoic acid was lower than that from the parent strain.