The behavior of electromagnetic scattering from two unidentical semi-circular bosses above a cconducting half-space is investigated. The image theorem is used to account for the specular reflection from the infinitely-extended half space. Both incident and scattered fields are expanded in Fourier series of azimuth angles with unknown coefficients. By enforcing the boundary conditions on the tangential E and H field continuity along two perfectly conducting circular cylinders, the expressions for the scattered fields are obtained. Numerical computations are performed to examine the bistatic and backscattering angular behavior of the scattering coefficients, and the results are compared to first-order scattering results. The relative importance of multiple scattering resulting from two adjacent bosses is discussed in terms of the boss-size, spacing, polarization, and operating frequency.