The effects of surface waves on sound propagated from a continuous wave source over a range of 300 it in water of depth 10 ft have been examined. It is found that the surface waves induce regular amplitude and phase fluctuations in the received signal. The dependence of the amount of amplitude and phase fluctuation on crest to trough height of the surface waves has been obtained for acoustic frequencies in the range 1 to 10 kc. Frequency spectra of the fluctuations, for values of the ratio of sound wavelength (λ) to wave height (A) above 18, are the same as the surface wave spectra. For values of λ/Aless than 18 the fluctuation spectra are broader and show well defined second and sometimes third harmonic components. Wave packet experiments in which the bow wave of a small boat is propagated across the length of the otherwise calm duct surface show that in the case of the uniformly rough surface the fluctuations are produced only by surface waves near the source and near the receiver.