Two children complaining of sleep apnea presented with brain stem gliomas. In the early stage of their illness, neurological disorders were too subtle to be recognized as significant by the physicians or to be noted by the parents. Case 1 experienced an episode of unsteady gait and weakness in the bilateral arms, at the age of 5. When it recurred after 7 years of remission, the predominant symptom was sleep apnea. Case 2 exhibited nasality of speech as the earliest sign of this illness very early in his life, presumably 5 years before the diagnosis of brain stem glioma. A slight sleep apnea which developed afterwards did not draw attention of the physicians because no neurological signs other than paralyses of the bilateral soft palates were present. MRIs of the both cases revealed diffuse, infiltrating lesions in the pons, the medulla oblongata and the upper cervical spinal cord. Both cases shared some features: (1) diagnostic delay of several years from the first symptom; (2) the main lesion in the medulla oblongata, where important structures for respiratory control are identified; (3) infiltrative growth patterns in the MRI of the tumor, which might account for the uncommon clinical courses.