PET, SPECT, and MR imaging are valuable techniques in the diagnosis and treatment of the epilepsies. MR imaging displays structural disturbances such as neoplasms; dysplasias, and atrophy with great sensitivity. Recent advances in MR technology also will permit the imaging of cerebral blood flow. PET and SPECT show physiologic derangements in epilepsy, including localized reductions in cerebral blood flow and metabolism and highly focal decreases in neurotransmitter receptor binding. These methods are particularly valuable when combined with electroencephalogram evaluation in selecting patients for epilepsy surgery. MR imaging is also a valuable diagnostic tool in the routine care of epilepsy patients.