Abstract. We investigate the sufficient conditions and the necessary conditions on an exchange ring R under which R has stable range one. These give nontrivial generalizations of Theorem 3 of V. P. Camillo and H.-P. Yu (1995), Theorem 4.19 of K. R. Goodearl (1979Goodearl ( , 1991, Theorem 2 of R. E. Hartwig (1982), and Theorem 9 of H.-P. Yu (1995). We call R has stable range one provided that aR+bR = R implies that a+by ∈ U(R) for a y ∈ R. It is well known that an exchange ring R has stable range one if and only if A ⊕ B A ⊕ C implies B C for all finitely generated projective right R-modules A, B, and C. It has been realized that the class of rings having stable range one has good stability properties in a K-theoretic sense (cf. [8,13]). Many authors have studied stable range one conditions over exchange rings such as [1,2,4,5,6,7,15,16].In this paper, we investigate stable range one conditions over exchange rings by virtue of Drazin inverses, nilpotent elements, and prime ideals. We showed that stable range conditions can be determined by Drazin inverses for exchange rings. Also, we see that these stable range conditions can be determined by regular elements out of any proper ideal of R. Moreover, we prove that an exchange ring R has stable range one if the set of nilpotents is closed under product. These extend the corresponding results of [4, Theorem 3], [9, Theorem 4.19], [12, Theorem 2],and [16, Theorem 9].Throughout this paper, all rings are associative ring with identities and all right R-modules are unitary right R-modules. M ⊕ N means that right R-module M is isomorphic to a direct summand of right R-module N. The notation x ≈ y means that x = uyu −1 for some u ∈ U(R), where U(R) denotes the set of all units of R. Call a ∈ R is regular if a = axa for some x ∈ R and a ∈ R is unit-regular if a = aua for some u ∈ U(R).