The myth of Osiris was an important myth in Ancient Egypt since antiquity, this is proved by its presence in the Pyramid Texts. According to the myth, Seth dismembered his brother Osiris into fourteen parts, that were buried later at fourteen different Egyptian sites in Upper and Lower Egypt. Most of these burial places became cult centers for the god. Two specific centers were more important and received actual and symbolic visits, namely AbDw, capital of the 8^th Nome of upper Egypt, where Osiris' head was thought to be buried and Ddw, capital of the 9^th Nome of lower Egypt, where Osiris' vertebral column was thought to be buried. These two cult centers were mentioned in religious books, they had fixed annual festivals and were linked to god Osiris' epithets and titles. The research aims at analyzing these two cult centers, their historical background before and during being a cult center of the god Osiris. The paper also aims at comparing between the two cult centers in regards to festivals and ceremonies, their existence in religious contexts and the timing when they flourished. The paper ends with a main conclusion.