This study investigates the problem of the natural universal (kull? ?ab???) in the works of Mull? ?adr? (d. 1640). When the problem of universals made its way into the works of Islamic philosophers such as Avicenna, it was transformed into the problem of the natural universal (kull? ?ab???) since the latter identified three different types of universals, and dispute broke out as to whether or not the natural universal exist in the external world. For Avicenna as well as for Mull? ?adr?, the natural universal is none other than quiddity considered in an absolutely unconditioned manner. Attention has been paid to those who pointed to the impossibility of the external existence of natural universals. The deniers of natural universals in the extra-mental world argue that since individuals share contradictory properties, natural universals cannot be co-extensive with its particulars. At the heart of their argument lies the assumption that natural universals have numerical unity, which both Avicenna and ?adr? reject. However, the problem of natural universals was further transformed in the writings of ?adr? based on his doctrine of the primacy of being. The doctrine of the primacy of being states that it is wuj?d that reveals the real faces of entities, and not quiddity. After proving the validity of the primacy of being, ?adr? thus relegates the notion of quiddity to shadows, aspects, determinations etc. of being. Naturally, in such a philosophical system, the natural universal or quiddity qua quiddity becomes an “accidental existent”—something that requires wuj?d for its existentiation. Thus ?adr? strips the natural universal of its independent existence. Consequently, natural universals become post rem in the ?adrian perspective. However, ?adr? does not deny that natural universals exist in the external world. Rather, he reinterprets it in light of the primacy of being in which it exists by means of wuj?d and not independent of it.