A case of a 4-year-old child with bobble-head doll syndrome (BHDS) caused by a suprasellar arachnoid cyst and successfully treated by endoscopic cystovenriculostomy is reported from Medisch Centrum Haaglanden, The Hague; and Academical Hospital Nijmegen, The Netherlands. The cyst collapsed and the aqueductal obstruction resolved. Early surgical treatment of BHDS with suprasellar cyst is recommended to prevent permanent neurologic damage and psychomotor retardation. 
COMMENT. Endoscopic treatment of a suprasellar arachnoid cyst relieved aquductal obstruction, and an associated bobble-head doll syndrome resolved. BHDS, characterized by a 2-3 Hz back-and-forth head movement, is caused by a suprasellar arachnoid or third ventricular cyst, and less often is secondary to aqueductal stenosis or VP shunt dysfunction. The tremor disappears in sleep and is increased by walking and excitement. It affects children younger than 10 years of age, and may present with macrocephaly, symptoms of raised intracranial pressure, optic nerve atrophy, ataxia, endocrine disorders (small stature, obesity, precocious puberty) or mental retardation. Thirty cases have been reported since the first description by Benton JW and associates , and are reviewed by the authors.