Neuroimaging has an important role in the investigation and treatment of patients with epilepsy. Diagnosis of the underlying substrate in a given patient with epilepsy determines prognosis with higher accuracy than electroencephalography. Neuroimaging techniques include computed tomography (CT) and magnetic resonance imaging (MRI), although CT has a diminished role for diagnosis. MRI is the most appropriate imaging technique in the initial investigation of patients with epilepsy. MRI is the most sensitive technique for the diagnosis of hippocampal sclerosis, tumors, and malformations of cortical development. MRI is also critical for neurosurgical planning. Other imaging techniques such as positron emission tomography (PET) and single photon emission computed tomography are reserved for patients with intractable epilepsy when surgery is contemplated. New developments such as MR spectroscopy, receptor PET, and magnetic source imaging are becoming clinical tools and have the promise of improving diagnosis.