This essay examines the costumes for gods and priests in ancient Mesopotamia as they are depicted in various documents and artifacts of the period, and it is part of an ongoing project that studies the process in which the religious costumes, the means of religious communication, of ancient Mesopotamia had evolved. The study shows that the religious costunmes in ancient Mesopotamia have following characteristics. 1. The costumes for gods are the same as those for men, including warp-around skirts, tierd skirts, shawls, and tunics. However, there are some differences : costumes for gods include such distinguishing features as aprons and long tassels. 2. Both wear stylized headpieces that indicate their divinity and have long hair and long beard. 3. As for shoes, the Sumerian and Babilonian gods go barefoot, but the militant Assyrian gods wear sandals. 4. Sumerian and Babilonian figures do not have much, but the Assyrian gods wear various ornaments including earrings and bracelets that emphasize their muscular physique. 5. Priests wear weird skirts or wrap-around skirts but no top. They have shaved hair to indicate their role as purifiers, but some of them have long beards.