The paper deals with the analysis of cables in stayed bridges and TV-towers, where the excitation is caused by harmonically varying in-plane motions of the upper support point with the amplitude ;. Such cables are characterized by a sag-to-chord-length ratio below 0)02, which means that the lowest circular eigenfrequencies for in-plane and out-of-plane eigenvibrations, and , are closely separated. The dynamic analysis is performed by a two-degree-of-freedom modal decomposition in the lowest in-plane and out-of-plane eigenmodes. Modal parameters are evaluated based on the eigenmodes for the parabolic approximation to the equilibrium suspension. Superharmonic components of the order n, supported by the parametric terms of the excitation and the non-linear coupling terms, are registered in the response for circular frequency K /n. At moderate ;, the cable response takes place entirely in the static equilibrium plane. At larger amplitudes the in-plane response becomes unstable and a coupled whirling superharmonic component occurs. In the paper a "rst order perturbation solution to the superharmonic response is performed based on the averaging method. For K(m/n), m(n, the geometrical non-linear restoring forces gives rise to a substantial combinatorial harmonic component with the circular frequency (n/m) . Both entirely in-plane and coupled in-plane and out-of-plane responses occur. Based on an initial frequency analysis of the response, an analytical model for these vibrations is formulated with emphasis on superharmonics of the order n"3 and combinatorial harmonics of the order (n, m)"(3,2). All analytical solutions have been veri"ed by direct numerical integration of the modal equations of motion.