We report a 11 year-old boy with adrenoleukodystrophy (ALD), who gradually became inattentive and hyperactive after ten years of age. His parents consulted with school counselor and were told that he might have attention deficit hyperactivity disorder (ADHD). We noticed his deterioration in intelligence and behavior and his cranial magnetic resonance imaging revealed bilateral abnormal intensity areas predominantly in the left frontal lobe to the basal ganglia, which surroundings was enhanced by Gd-DTPA suggesting demyelination. Statistical parametric mapping (SPM) using IMP single photon emission tomography showed decreased cerebral blood flow in the left frontal cortex, cerebellum, and brain stem. Abnormal levels of plasma very-long-chain fatty acids and genetic testing confirmed the diagnosis of ALD. His behavioral problems transiently improved with methylphenidate treatment, however he died in spite of bone marrow transplantation. This report emphasize that the importance of early medical evaluation when ADHD-like symptoms became prominent in a child who never had such problems before. Recognition of ADHD in the field of education enhanced after the recent promotion of special needs education. Necessity of medical evaluation in such a child to school teachers, nurses, counselors should be emphasized, so as not to be left undiagnosed and untreated.