The aim of this study was to analyze the outcomes of treatment of necrotizing soft-tissue infections (NSTIs) in the feet of diabetic patients and to determine factors associated with limb salvage and mortality. A retrospective study of a consecutive series of 145 diabetic patients suffering from NSTIs treated in the Diabetic Foot Unit, La Paloma Hospital was done. NSTIs were classified as necrotizing cellulitis if it involved the subcutaneous tissue and the skin, as necrotizing fasciitis if it involved the deep fascia, and as myonecrosis in those cases where muscular necrosis was present. In the necrotizing cellulitis group (n = 109), 8 (7.3%) major amputations were performed. In the necrotizing fasciitis group (n = 25), 13 (52%) major amputations were undertaken. In the myonecrosis group (n = 11), 6 (54.5%) major amputations were performed. Predictive variables related to limb loss were fasciitis (OR = 20, 95% CI = 3.2-122.1) and myonecrosis (OR = 53.2, 95% CI = 5.1-552.4). Predictive variables of mortality were age >75 years (OR = 10.3, 95% CI = 1.9-53.6) and creatinine values >132.6 micromol/L (OR = 5.8, 95% CI = 1.1-30.2). NSTIs of the foot are an important cause of morbidity and mortality in diabetic patients.When fascia and/or muscle are involved, there are significant risks of major amputation.