It seems that recent studies in Aegidius of Rome are making corrections to Mandonnet's view on his Thomism. P. Nash is of opinion that Aegidius can scarcely be called a Thomist because of there being an observable tendency to the essentialism and the universal hylomorphism in his metaphysics. For instance, though he certainly maintained a real distinction between esse and essentia, Aegidius exaggerated it and consequently reified esse and essentia; esse is the second act, and the first act is form, so that, metaphysically speaking, essentia has the priority; moreover Aegidius found formal and material element in all creatures. The aim of this article is to study cautiously the Quaestiones disputatae de esse et essentia and then to examine the legitimacy of Nash's interpretation mentioned above. In our opinion Nash does not correctly understand the meaning of esse in Aegidius and naturally does not pay sufficient attention to what Aegidius intended to show, Aegidius carefully distinguished between the entitative order and the essential one, asserting emphatically the absolute priority of esse to essentia; in fact, he stated explicitely that esse is ≪primus actus≫,≪perfectissimum≫ and ≪summa actualitas≫.