A case of infantile spasms associated with unilateral gangliocytoma in the right parietal motor area was described. A 7-month-old boy with normal prenatal, perinatal and early postnatal course developed infantile spasms consisting of sudden flexion of the neck and trunk and forward flexion of the arms. Focal signs were not present. The head size was normal. There was no depigmentation of skin. Fundoscopic tests were negative. The electroencephalogram showed a hypsarhythmic pattern. Routine laboratory tests were normal including CT scan.At 11 months the seizures became more intractable despite treatment with administration various anticonvulsants, ACTH, γ-globlin and DN-1417. Mild paresis of the left foot and developmental delay were found. A CT scanning revealed a large high density area in the right parietal area. A gangliocytoma was removed partially at 2 years of age. His seizures and paresis were improved mildly.