Necrotising fasciitis is a rare but life-threatening infectious disease emergency. Delays in diagnosis and treatment are common, and mortality rates often exceed 30%. Successful management of this disease requires high clinical suspicion and aggressive action. The mainstays of therapy include early and wide surgical debridement, antibiotics and supportive care, with prompt surgical intervention. Adjunctive modalities, such as protein synthesis inhibitors, hyperbaric oxygen and intravenous immunoglobulin, may have a role, but their effectiveness remains unproven. New rapid diagnostic tools are emerging that promise to revolutionize early detection of necrotising fasciitis. Research into the molecular microbiology, especially regarding group A streptococcus, are providing novel insights into the pathogenesis of necrotising soft tissue infections and identifying future targets for rationally designed interventions.