The current article examines four case studies of complex genealogies in Mesopotamia from the 3rd and 2nd millennia BCE. The first three case studies are focused on the complex genealogies used by 3rd millennium BC kings in the Early Dynastic Period III, in Lagaš II, and in the period of 3rd Dynasty of Ur. The fourth case study deals with Assyrian king Tukultī-Ninurta I (1242–1206 BCE).