The effect of pre-stress on the scattering of plane SH-waves from a circular cylindrical cavity in a compressible isotropic elastic medium, is studied. The complex function method is employed to analyze the incremental boundary value problem. The spatial variables (x1, x2) are mapped onto two different complex planes so that the series solution of the incident waves and the scattered waves are expressed as functions of two different complex variables. The coefficient of each tam in the series solution can be computed numerically from a set of linear simultaneous equations, which are constructed by satisfying the incremental traction-free boundary condition along the surface of the cavity. Varga material is assumed in the numerical examples. Varying the principal stretches, the effect of pre-stress on the dynamic stress concentration factor and the scattered energy is investigated.