Kinsbourne's syndrome (ataxia--opsoclonus--myoclonus) is described. The characteristics of this syndrome are: infections of the upper respiratory tract and enteric system and behavioural disturbances leading to the typical symptomatological triad. Various tests were carried out to determine the presence of neuroblastoma which is often associated (46%) to this syndrome. These tests resulted negative. Differential diagnosis was considered in relation to other conditions which present a characteristic symptomatology similar to Kinsbourne's syndrome. Synthetic ACTH (Synacthen) treatment produced a regression of the clinical symptoms. Based on the examinations carried out, which always resulted negative even after 36 months, and on the drug dependence, the present case was diagnosed as primitive opsoclonus.