Ewing's sarcoma is a rare malignant neoplasm that comprises approximately 4-6% of primary bone tumors. In most cases, femur and pelvis are affected, and less commonly the head and neck areas (in the jaws, usually the mandible). These tumors have been reported more frequently in males, mostly aged 5-20 years old. Systemic symptoms and signs such as fever, weight loss, anemia, leukocytosis, and elevated erythrocyte sedimentation rate (ESR) may be the first signs in oral Ewing's sarcoma. Such signs and symptoms are also seen in odontogenic infections and abscess. In one case, the patient went to a dentist with pain, swelling, and abscess similar to odontogenic infection and patient's tooth was pulled due to misdiagnosis. This tumor has an aggressive clinical behavior and is identified with rapid growth and high probability of metastasis at diagnosis. Thus, it is necessary to differentiate it from a dental abscess. As for the treatment of Ewing's sarcoma, first the tumor must undergo chemotherapy to reduce its size and, eventually, it undergoes extensive surgery. This case report deals with a 16-year-old patient wrongly diagnosed with odontogenic infection and abscess, and hospitalized. As the symptoms did not remit, biopsy was carried out and the patient was operated on with Ewing's sarcoma diagnosis.