Beta-hemolytic, pyogenic streptococci are classified according to type of major surface antigen into A (Streptococcus pyogenes), B (Streptococcus agalactiae), C (multiple species including Streptococcus dysagalactiae) and G (multiple species including Streptococcus canis) Lancefield groups. Group A Streptococcus causes each year hundreds of thousands deaths globally as a result of infections and post-infectional sequelae. An increasing number of severe, invasive infections is caused by selected, specialized pathogenic clones. Within the last 50 years, an increasing number of human infections caused by groups B, C and G Streptococcus (GBS, GCS, GGS) has been observed worldwide. GBS was first identified as animal pathogen but the spectrum of diseases caused by GBS quickly shifted to human infections. Groups C and G Streptococcus are still regarded mostly as animal pathogens, however, an increased number of severe infections caused by these groups is observed. The increasing number of human infections caused worldwide by GCS/GGS can be a sign of similar development from animal to human pathogen as observed in case of GBS and this group will gain much more clinical interest in the future.The situation in Poland regarding invasive infections caused by pyogenic streptococci is underestimated.