This article considers all the Mulla sadra’s proofs of primacy of existence (asalat al-wujud) found in all his works‚ and concludes that sadra has two approaches in his arguments: (1) to prove the primacy of existence through negation of original attributes from quiddity (mahiyyah), (2) to refute the primacy of quiddity through indirect proof. At the end‚ we conclude that the first approach and the arguments based upon it are stronger than the other.