MR is the imaging technique of choice when examining a patient who is having seizures. Detection, localization, and differentiation of structural epileptogenic abnormalities are much better with MR imaging than with CT. MR imaging has a high success rate in identifying hippocampal sclerosis, a common cause of surgically treatable temporal lobe epilepsy. The affected hippocampus is atrophic and hyperintense on long TR images. Functional imaging with single-photon emission computed tomography and positron emission tomography is complementary to MR imaging but is not as widely available. In summary, MR imaging has dramatically changed the workup of epilepsy, especially for the patient with medically uncontrollable seizures. As surgical treatment of epilepsy becomes more available, the need for preoperative evaluation with MR imaging will increase.