The reflection and transmission coefficients of electromagnetic waves, whose transverse electric and magnetic field components possess a given symmetric distribution, have been determined by the rigorous analysis of these components at the aperture plane of a semi-infinite chiral slab, either embedded between two semi-infinite dielectric media and placed in front of an air half space, or totally immersed in a uniform dielectric medium. The discrete spectrum of incident and reflected surface modes as well as the continuous spectrum of reflected and transmitted modes have been taken into consideration in this analysis. The ensuing integral equations have been transformed, by using an appropriate complete set of basis functions, into a system of algebraic equations which have been solved numerically. The tangential components of the electromagnetic field at the aperture plane, the radiation field in the far region, as well as the transmission and reflection coefficients variation as a function of chirality have been obtained, and different excitation schemes have been analyzed. ©2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 24: 335–340, 2000.