Necrotizing soft-tissue infection (NSTI) is a bacterial infection with necrosis of the cutaneous, subcutaneous tissue and fascia with sparing of the underlying muscle. The most frequent initiating factor reported, for necrotizing fasciitis, in the head and neck region is a primary odontogenic infection or postextraction infection, abrasion, and laceration of the face or scalp. Necrotizing fasciitis can progress rapidly to systemic toxicity and even death if not promptly diagnosed and treated. If the patient has any risk factors, this can worsen the prognosis. In this study, 2 cases of NSTI with dental pathology history (one with the spreading to mediastinum and the other spreading to suprahyoid) were discussed with a review of the literature. One of the cases had diabetes mellitus, but interestingly, she had a better prognosis, and she was discharged asymptomatic. In addition, the other case had no any risk factors, but he had a worse clinical cranial nerve paralysis (a rare complication of NSTI) and died. As a conclusion, despite the intensive therapy, large debridement, and antibiotics with large spectrum, the delay in the patient's diagnosis and treatment increased mortality. We aimed to attract attention to the importance of dental pathologies and early diagnosis.