Cognitive dysfunction is one of the major contributors to the burden of epilepsy. It can significantly disrupt intellectual development in children and functional status and quality of life in adults. There is major evidence confirms that cognitive impairment can appear or worsen with early and chronic progressive neurologic changes in epilepsy. It has been increasingly accepted that comorbidity does not indicate causality. Certainly, cognitive impairment in epileptic patients warrant crucial evaluation and mitigation from the time of diagnosis and treatment of epilepsy. The concept of a bidirectional nature of cognitive impairment in epilepsy represents a change in the paradigm of neuropsychology of epilepsy. It has been suggested that both behavioral and cognitive dysfunction associated with epilepsy are not necessarily the consequence of active epilepsy but in fact can dominate and be associated with factors before emergence of epilepsy. This review discusses different etiologies of cognitive and behavioral comorbidities in epilepsy and tries to clarify the nature of relation between epilepsy and cognition.