An invasive beta-haemolytic Lancefield group A streptococcal (GAS) infection was diagnosed in 4 patients: a 70-year-old woman, her 71-year-old husband, a 62-year-old woman and her 43-year-old son. In the married couple the infection was caused by GAS-type TB3264M100. The woman had a pneumonia, whilst her husband developed a streptococcal toxic shock-like syndrome; he died. The other woman and her son were infected with GAS-type T6M6. The son died of a circulatory arrest due to necrotizing fascitis from a wound in his arm. His mother recovered following a severe tonsillitis. The number of invasive GAS infections has increased in the past decades. GAS infections occur mostly in isolated cases, but clusters of patients are also seen, like the two described here. The risk of an invasive GAS-infection is greatest if one has been in the neighbourhood of the index patient during the week prior to the diagnosis in that patient. According to the latest (American) guidelines, there is no reason for prophylactic treatment of the close contacts of patients.