Shallow‐water ambient‐sea‐noise measurements in the frequency range 20 3000 cps have been made in the Gulf of St. Lawrence off the north coast of Prince Edward Island, with and without ice cover. The presence of ice is found to make a large difference both to the level and to the spectral distribution of the ambient noise. Result,are presented that illustrate both the effect of ice cover on the ambient noise and the transition from the “open‐water” to the “ice‐cover” condition.