Congenital ocular motor apraxia (COA), first described by Cogan in 1953, is a rare disorder which shows characteristic defects of the horizontal voluntary saccades, and compensatory head thrust. Until now, most cases have showed a presumably congenital origin, bilaterality, and a tendency to various stages of recovery with aging. But the cause and mechanism of COA are not completely known. Occasionally, it combines with other neurologic abnormalities and metabolic diseases such as Gaucher's disease exhibit similar clinical characteristics to COA. We recently experienced a case of a 3-year-old girl who showed the clinical features of unilateral congenital ocular motor apraxia.