Streptococcus pyogenes is a Gram-positive, group A Streptococcus (GAS), responsible for several diseases in children and adults. lnvasive GAS disease is a severe, lifethreatening infection, in which the bacteria invades the bloodstream, internal organs, or connective tissue. Therapy of GAS infection consists of targeted antibiotics and supportive care. ln our case report we would like to present 9-month-old dizygotic twins with different outcomes ol invasive GAS infection.  Kulcsszavak: invasive GAS infection, Streptococcus pyogenes, MBL