A comparison was made of the pigment-forming capacity and the enzymatic activity, growth rate, virulence and sensitivity to antibiotics and egg lysozyme in 397 pigment, 203 pigment-free strains of staphylococci and 24 pigment-free Staph aureus mutants. Pigment formation did not always correlate with the general biological activity of the cultures, the rate of their growth and the sensitivity to antibiotics and lysozyme. Pigment-free staphylococcus mutants retained the principal properties of the initial strains (including the virulence and sensitivity to antibiotics and egg lysozyme) more frequently. It is supposed that the marker determining the pigment formation in staphylococci was not connected with the markers determining the most significant pathogenicity properties and also antibiotic resistance.