This article shows the close relationship that exists between two fundamental concepts in the theological doctrine of Origen of Alexandria: “fullness” and“participation”. These two concepts have been the subject of many earlier studies. However, they treated the topic in a more restricted sense, exploring very specific aspects of Origenian theology. The originality of this study lies in demonstrating how both concepts recur frequently in his theological thinking, give it a framework and hold his thought together. They consequently systematize and make possible a perfect synthesis of all his thinking.