Surname Йерко (Jerko 
, Йерко 
) , across the world, is a rare last name. The cognomen Йерко is habitual in Slovenia, where it is quite a rare surname, Croatia, where it is a rare surname, and Hungary. Not in comparison with a country's population, this name is the most popular in Hungary, Slovenia, and Egypt. More frequently, Йерко is the forename as well as the last name.