Extramedullary infiltration is common in acute myeloid leukemia (AML) patients. Although AML can cause neurological symptoms, especially when associated with extramedullary infiltration, a presenting manifestation of facial palsy is rare. We report on a 1-year-old boy who developed right facial palsy. Detailed examination led to a diagnosis of AML (French-American-British classification M1). Magnetic resonance imaging enhanced with gadolinium-diethylenetriamine penta-acetic acid showed abnormal enhancement of the right facial nerve, which disappeared after chemotherapy. AML should be considered as a differential diagnosis of facial palsy. Enhanced magnetic resonance imaging may be useful for diagnosing facial palsy associated with AML and for evaluating treatment outcome.