Abstract: The stability of edge dislocations in a nanoscale cylindrical inhomogeneity with interface stresses is investigated by means of a complex variable method. The explicit expression for the image force acting on the edge dislocation is obtained. The critical radius of the inhomogeneity of the dislocation stability in the nanoscale inhomogeneity is derived. The influence of the interface stresses on the critical radius of the inhomogeneity is evaluated. If the material constants and the radius of the inhomogeneity are fixed, a critical value of the shear modulus or the Poisson’s ratio of the matrix may exist, which can change the edge dislocation stability in the inhomogeneity. The critical radius of the inclusion increases with the decrease of the shear modulus or the Poisson’s ratio of the matrix. In addition, the interface stresses can not only change the property of the edge dislocation stability in the nanoscale inhomogeneity, but also change the value of the critical radius of the inhomogeneity under certain conditions.