Dysfunction of the hypoglossal nerve (nervus hypoglossus) occurs usually as part of a larger symptom complex, only rarely being the sole symptom of a neurologic disorder. Peripheral etiology must also be kept in mind, especially in patients with malignant primary disease. We describe a patient who developed an isolated right hypoglossal nerve palsy, which later became bilateral. In computerized tomography the bones of the cranial base of the patient with prostatic cancer were damaged by metastases especially in the vicinity of hypoglossal canals.