AIM OF THE STUDY: Analysis of data on the occurrence of severe infections caused by group A streptococci, emm typing of the isolated strains, and survey of resistance to the selected antibiotics. MATERIAL AND METHODS: In 2012 and 2013, 43 S. pyogenes strains were isolated from severe infections. The isolates were most often recovered from wounds and abscesses (36 patients), followed by blood culture (5 patients), sputum (1 patient), and autopsy samples (1 patient). Antimicrobial susceptibility to selected antibiotics ( penicillin, erythromycin, clindamycin, spiramycin, and tetracycline) was tested by the disk-diffusion method and the minimal inhibitory concentrations (MICs) were determined. RESULTS: In 2012 and 2013, an increase in severe streptococcal infections was observed, with 27 and 16 cases reported, respectively. Resistance to macrolides was detected in 18.5% and 12.5% of isolates, respectively, and resistance to tetracycline in 25.9% and 20% of isolates, respectively. The isolated S. pyogenes strains were most often assigned to emm type 1. Risk factors for streptococcal infection were analyzed, with injury being most often identified as a risk factor- in seven and two patients, respectively. The patients were most frequently treated by beta-lactam antibiotics (penicillin and ampicillin). In 2012, two cases were fatal. CONCLUSION: This study reports cases of invasive group A streptococcal (GAS) infection as seen in clinical practice. An increased occurrence of S. pyogenes was observed in the hospital, with the isolates exhibiting elevated resistance to erythromycin and tetracycline. It is necessary to monitor the trends of antimicrobial resistance and the distribution of emm types among group A streptococcal isolates. Cooperation of the laboratory and clinical professionals in the prevention and therapy of streptococcal infections, invasive in particular, is crucial for risk reduction.