Summary: Inconsistent and inaccurate death certification, lack of agreed definitions, different terminology, and different understanding of the same terminology hamper research into mortality in epilepsy and result in national statistics that are difficult to interpret. A consensus in death certification and in classification of epilepsy-related deaths, including sudden unexpected death in epilepsy (SUDEP), is needed. Guidelines for classifying cases as SUDEP are proposed. Their aim is to allow uniformity and comparability between studies. These guidelines take into account the limits of the information usually available in this setting even when these deaths are investigated. The guidelines are complemented by those dealing with identified deaths in epidemiologic studies where data are lacking.