The article briefly surveys the epidemiology of Streptococcus pyogenes caused disease in Norway during the last 15 years based on notification data, with emphasis on the nation-wide outbreak in 1987-88 caused by mucoid M-1 organisms. During the season S. pyogenes infections was 60% higher than expected. The number of bacteraemia cases, many with fulminant septicaemia, showed an almost threefold increase compared with earlier years. Unusual clinical manifestations such as necrotising fasciitis, pneumonia with empyema, primary peritonitis and meningitis also occurred. We briefly review the known virulence factors of S. pyogenes in an attempt to improve our understanding of the shift in clinical manifestations and occurrence of the disease.