Scientific BACKGROUND: Although the association of cerebellar dysplasia/hypoplasia with cerebral cortical development malformations such as lissencephaly, periventricular nodular heterotopia, subcortical band heterotopia has been described, the association of cerebellar hypoplasia with schizencephaly has not been described before in the literature. CASE: A 41 year-old male patient was admitted to our outpatient clinic because of epilepsy. He had a history of seizures a few times a year since he was 15 years old. His neurologic examination demonstrated nystagmus with the fast phase beating in the direction of gaze, intentional tremor, truncal ataxia and mild mental retardation. He had undergone magnetic resonance imaging (MRI) for the first time in his life. MRI examination revealed severe cerebellar hypoplasia and schizencephaly in the medial temporal lobe. CONCLUSION: We discuss potential genetic defects that could lead to both cerebral cortical malformations and posterior fossa malformations especially cerebellar hypoplasia