Rotary drilling equipment was modified and used to obtain cores from glaciers in Northwest Greenland, Byrd Station and Little America V, Antarctica. Using cold compressed air, specially designed bits and other modifications, cores were obtained to 1345 feet in Greenland, 1000 feet at Byrd Station and the Ross Ice Shelf was penetrated to a depth of 840 feet at Little America V. In all locations cracks in the core appeared with increasing frequency at depth due to the sudden release of the overburden load when the core was cut in the air-filled hole. Special equipment and techniques developed dealt with the problem with some success. (Author Modified Abstract).