Group A beta-haemolytic streptococcus is a well-known cause of necrotising fasciitis, which is increasing in incidence and severity. More aggressive soft tissue infections of the hand and upper extremity caused by this organism have been noted in our plastic surgical unit, prompting a five-year retrospective study to find out which factors affect clinical outcomes. The records of 31 patients, 27 male and 4 female, with Group A beta-haemolytic streptococcal soft tissue infections with a mean (SD) age of 25 (12) years were reviewed. Twenty-seven infections followed injuries, while four were spontaneous. Six patients required more than two operations to clear the infection, and one required free tissue transfer for closure of the resulting soft tissue deficit. Of the variables age, number of cigarettes consumed daily, interval from the date of injury to the date of presentation, coexisting infection with Staphylococcus aureus, and grade of infection at presentation, only the last correlated with the patients' clinical course (p<0.001). Those patients with spontaneous infections with pre-existing medical conditions had a worse prognosis, requiring more operations and a longer stay in hospital. A multicentre prospective study would be useful to confirm these findings.