We retrospectively studied 32 patients who had cortical dysplasia and epilepsy. Cortical dysplasia was classified into diffuse cortical dysplasia (8 patients), bilateral localized cortical dysplasia (5), unilateral diffuse cortical dysplasia (2), and focal cortical dysplasia (17). The onset of epilepsy was younger in patients with more widespread lesions. At the onset, patients with bilateral lesions generally had symptomatic generalized epilepsy, while those with unilateral cortical dysplasia tended to have symptomatic localization-related epilepsy. In patients with focal cortical dysplasia, however, 4 patients had West syndrome, either at the onset of epilepsy or during the follow up period. Seizure outcome was poor in any type of cortical dysplasia. An evaluation of prognostic factors in patients with focal cortical dysplasia did not show any of statistical significance, including gender, age at onset of epilepsy, psychomotor delay and the presence of high intensity areas in T2-weighted MRI.