Introduction: Necrotizing fasciitis is a rare and severe infectious disease with infectious necrosis often extending in depth to the subcutaneous tissue in the absence of rapid medical-surgical treatment. We report two cases of necrotizing fasciitis of the thigh, which underline the principle clinical and therapeutic characteristics of this often underrated disease., Observation: The first case concerns a young 21 year-old woman without remarkable medical history who, following injury from the thorn of a palm tree, developed an aerobic germ necrotizing fasciitis which regressed following medical-surgical treatment. The second case concerned a 46 year-old man suffering from diabetes and arteritis, who having presented an infection following the amputation of the large toes, developed fatal necrotizing fasciitis., Comments: This disease corresponds to infectious necrosis of the subcutaneous tissue and is essentially characterized by its rapid, occasionally violent, progression. It represents a surgical emergency and requires early and extensive incision in order to avoid severe functional after effects, or even death of the patient. Only enhanced education of the physicians leading to rapid clinical diagnosis will improve the prognosis which still remains fearsome.