Chédiak-Higashi syndrome (CHS) in children can be a fatal disease. We describe the oldest known CHS patient first seen with a neurologic disorder in early adult life. From the age of 22, this 39-year-old woman developed mental deterioration, parkinsonism including resting tremor at the tongue, mandible, and hands, oculogyric crisis, muscular atrophy of limbs, and loss of tendon reflexes. MRI showed marked temporal dominant brain atrophy and diffuse spinal cord atrophy. Partial albinism, pan-leukocytic giant granules, and profoundly decreased NK-cell activity were compatible with childhood CHS, but apparently normal neutrophil function prolonged her survival. Stimulated proliferation of lymphocytes was less than 40% that of normal controls.