The interaction between a screw dislocation and an elliptical nano inhomogeneity embedded in an infinite matrix was investigated. The interface stress effects of the nano inhomogeneity were accounted for with the Gurtin–Murdoch model. The stress fields inside the inhomogeneity and matrix were then solved with the complex variable and conformal mapping method. The solution was of semi-analytical nature and was verified by studying a degenerated case wherein a screw dislocation interacts with a circular nano inhomogeneity. The image force on the screw dislocation was then calculated. The influences of the elastic mismatch between the inhomogeneity and matrix, the interfacial properties, the aspect ratio of the elliptic nano inhomogeneity and the position of the screw dislocation on the image force were systematically discussed. Analysis of a Screw Dislocation Interacting with an Elliptical Nano Inhomogeneity. J.Luo, Z.M.Xiao: International Journal of Engineering Science, 2009, 47[9], 883-93