Purpose. To study the composition of the oral cavity microflora in health and in patients with generalized periodontitis, to characterize the resistance of isolated microorganisms to antibiotics. Methods. Bacteriological examination of the samples of material from the individuals with varying severity generalized periodontitis in the acute stage has been done. The ability to filmformation of staphylococci isolates was studied in plastic plates. The sensitivity of clinical strains to antibiotics was determined by agar diffusion method with paper discs (NICF, Russia). Results. It has been shown that under generalized periodontitis microflora is mainly represented by the associations of: S. aureus, S. epidermidis, Bacteroides spp., Actinomyces spp., Candida spp., P. aeruginosa and Streptococcus spp. Among staphylococci, isolated under periodontitis, the ability to biofilmforming had 30.4% of S. aureus isolates, 82.9% – S. epidermidis, 25.0% – S. saprophyticus, that coincided with their resistance to lincomycin and erythromycin. The most effective to microflora of periodontal pockets there were ofloxacin (60 % susceptible strains, except Veilonella spp., Bacteroides spp.) and clindamycin (50% sensitive strains except P. aeruginosa, E. coli, Actinomyces spp., Veilonella spp.), erythromycin was the least effective (6.7–37.0% susceptible strains, except staphylococci and streptococci). Conclusions. It was shown that under generalized periodontitis the association of opportunistic microorganisms had a key role. The observed ability to filmformation among staphylococci isolates may be one of possible explanation of lincomycin and erythromycin resistance level increasing.