The lysozyme activity of 354 lysozyme-positive and 100 lysozyme-negative (by the results of qualitative test) staphylococcus strains were studied quantitatively. The method was based on titration of the lysozyme in the culture fluid of 48-hour broth cultures of the strains under study. The quantitative method proved to be more sensitive than the qualitative one, and permitted to reveal the lysozyme production in 71% of the strains which were formerly considered to be lysozyme-negative. There were distinct species differences between the lysozyme-positive staphylococci: the mean lysozyme level in the S. aureus was significantly greater then in the S. epidermis. There was no regular association between the lysozyme activity, staphylococcus origin, bacteriophage reference and the antibiotic resistance.