Corpus callosotomy is an effective, relatively low-risk, palliative procedure for a selected population of patients with medically intractable epilepsy. Here we describe this technique. METHOD: An interhemispheric microsurgical approach is performed. Neuronavigation facilitates orientation. The callosal body is transected through to the roof of the ipsilateral ventricle using an ultrasonic aspirator; the genu and rostrum are then identified and also split. If a total callosotomy is performed, transection of the splenium is performed with care given to preserve the crus of the fornix. CONCLUSIONS: Meticulous microsurgical technique and knowledge of the limbic system's anatomy is essential to keeping this procedure safe and effective.