The problem of scattering from a conducting cylinder above a lossy medium having a sinusoidal profile interface is investigated by combining an integral equation approach with the extended boundary condition method. The incident transverse magnetic electric field and the Green function of the problem are determined by applying the extended boundary condition method. The application of the method of moments to the integral equation over the cross section of the scatterer results in an infinite linear set of equations for the unknown expansion coefficients of the electric field inside the scatterer. This infinite set is truncated and solved numerically. Finally, the far field scattered in free space is evaluated by employing the steepest descent approximation, and several interesting conclusions concerning the influence of the sinusoidal profile on the scattered field are deduced.