Acute Lymphoblastic Leukemia (ALL) is the most prevalent hematological malignant tumor during childhood. Unilateral infiltration into the gums is less prevalent and more often observed in the AML type.A 12-year-old girl with symptoms of pain and swelling in the buccal vestibule and also at the posterior part of the right palate of the maxilla was referred to a private dental office. The patient had been inflicted by ALL and had undergone complete chemotherapy. A week prior to her admittance into the hospital, the workup of the patient's blood revealed her recovery. The clinical and radiographic evidence did not show any dental problems. The histological examinations on the patient's jaw revealed the correct diagnosis of ALL and the patient underwent chemotherapy for the second time.This case has been reported to point out that intraoral unilateral swelling of the upper jaw may be propounded as the primary diagnostic symptom of ALL.