The aim of study was to determine a production of proteinA in coagulase-negative Staphylococcus aureus (CNSA) or CF-negative S. aureus (CFNSA) strains. 59 CNSA and 18 CFNSA strains were isolated between 1997 and 2003 from different clinical specimens. The Protein A production was determined by immunoblotting method. The presence of protein A gene (spa) was investigated using the polymerase chain reaction (PCR). Two sets of phages and RFLP (Restriction Fragment Lenth Polymorphism) of coa gene method were used for typing strains. The results proved that the lack of ability of protein A production occurs more frequently in protein A-negative CFNSA strains with compare to the CNSA, which are protein A-positive for the majority of strains. Deficiencies of protein A, doesn't seem to be caused by the loss of spa gene. Protein A-negative CFNSA strains have phagotypes, RFLP and antibiotic resistant patterns which differ them from protein A-negative CNSA strains. Almost all of protein A-negative CFNSA and CNSA strains are resistant to methicillin.