Overhead lines operate under all weather conditions and, consequently, are subjected to various forms of aerodynamic excitation which can cause three types of oscillation to occur, namely aeolian vibration, subconductor oscillation and full-span galloping. The meteorological conditions, associated with each type of oscillation, are described and the attendant problems discussed. Solutions which have been developed to overcome these problems are described and the relevant research work is outlined. It will be shown how this work could affect the future designs of overhead lines at existing voltage levels. Finally, the problems associated with possible multi-subconductor u.h.v. lines are considered and the influences which these problems may have on the design of such lines discussed.