The paper outlines the priesthood in Mesopotamia. The first part shortly observes religion in the lands of Sumer and Akkad, as their amalgam, Mesopotamian religion as well. The second and the main part of paper presents names, grades and services of priesthood in Mesopotamia, as sacred kingship separately as well. Third part is dedicate to the temples in Mesopotamia and worship in their basis. The paper concludes by elementary and short revision of fast and day of rest.