In 1990, a combined land-sea experiment in the Hall Bredning, Scoresby Sund (East Greenland) revealed new information about the crustal structure of the Jameson Land Basin. The sediments and the upper and lower crust have been imaged by a 710-km-long network of seismic refraction lines. Our data indicate that the crust-mantle boundary is at a depth of 24 km close to the western coast of Jameson Land and deepens to 31 km toward the western termination of Hall Bredning. The sediments thin from 8-km thickness in the east to almost 0 km close to Milne Land. Our cross sections indicate that Jameson Land is an asymmetrical, half-graben shaped sedimentary basin with a N-S striking axis. ¿ American Geophysical Union 1996