Copeptin is a surrogate marker of the pituitary-secreted nonapeptide arginine-vasopressin (AVP) and has gradually replaced AVP in several clinical studies largely due to its structural and methodological advantages. Copeptin is a marker of non-specific stress response, and has been suggested to have clinical implications in a variety of cardiovascular and non-cardiovascular conditions. However, up to now there are no data available on copeptin in seizure disorders, neither in adults nor in children.