In recent years, there has been a rise in the number of invasive infections caused by Streptococcus pyogenes. The reasons for the observed increased prevalence of the disease are not entirely clear. The present study describes the cases of 6 children hospitalised over a course of one year with a diagnosis of invasive infection due to this pathogen. Three patients were diagnosed with acute post-streptococcal glomerulonephritis and pneumonia (complicated by pleural empyema in 1 patient). Two patients had erysipelas (including one case of recurrent erysipelas), and 1 patient was found to have an abscess in the border area between the femur and soft tissues. The study analyses the clinical course of infection, and highlights the importance of diagnostic tests, particularly the antistreptolysin O titre test, in confirming the infection triggered by Streptococcus pyogenes.