This paper concerns free vibration analysis of single-story multi-bay planar frame structures. An exact analytical solution is obtained using a wave vibration approach, in which vibrations are described as waves propagating along uniform structural elements and are reflected and transmitted at structural discontinuities. The coupling effects between bending and longitudinal vibrations in the multi-bay frames are taken into account. Both natural frequencies and modeshapes are obtained. Numerical examples are presented along with comparisons to results available in the literature.