Necrotizing fasciitis (NF) is a necrotizing soft tissue infection that can cause rapid local tissue destruction, necrosis and life-threatening severe sepsis. Predisposing conditions for NF include diabetes, malignancy, alcohol abuse, and chronic liver and kidney diseases. NF is classified into two categories (types 1 and 2) based on causative microorganisms. The initial clinical picture of NF mimics that of cellulitis or erysipelas, including fever, pain, tenderness, swelling and erythema. The cardinal manifestations of NF are severe pain at onset out of proportion to local findings, hemorrhagic bullae and/or vital sign abnormality. In such cases, NF should be strongly suspected and immediate surgical intervention should be considered, along with broad-spectrum antimicrobials and general supportive measures, regardless of the findings of imaging tests.