Background: Corpus callosotomy is a palliative surgical procedure involving partial or complete disconnection of the corpus callosum. It has been shown to improve outcomes of seizure control with in six months of the procedure. Here, we discuss a challenging case of intractable generalized epilepsy with a delayed response to corpus callosotomy. Methods: This report describes a 23 year old female with onset of seizures since age 16. Patient was followed over 7 year period for evolution of her seizures and treatment. Results: Patient experienced three different types of seizures including atypical absences, drop attacks and grand mal seizures. The most disabling type of seizures were the drop attacks associated with injuries. MRI showed bilateral subependymal heterotopia. Multiple EEG telemetry studies showed generalized spike waves without clear lateralization or focalization. Patient failed seven different antiepileptic medications, ketogenic diet and vagal nerve stimulation. Treatment with anterior corpus callosotomy started to show improvements at 18-24 months after the procedure with less severe drop attacks. Conclusions: Corpus callosotomy usually works few months after surgery. This is a very atypical case in whom callosotomy had a delayed response. This is rarely reported and we do not have a clear explanation. Delayed re-organization of the pathways associated with the seizure initiation may be a potential explanation.