The Bremer Basin underlies part of the upper continental slope of offshore southwest Australia. It occupies an area of 9000 km2, and contains a sedimentary pile probably 10 km thick in water depths of 200-3000 m. Though not tested by drilling, the basin is covered by a grid of seismic data. By analogy with the Eyre Sub-basin to the east, the Bremer Basin probably contains Late Jurassic to Barremian continental deposits overlain by Albian and Late Cretaceous marine deposits with a veneer of Tertiary open-marine carbonates of variable thickness. The Bremer Basin formed during the period of continental extension that preceded the breakup of Australia and Antarctica in the mid-Cretaceous. However, Triassic (?and older) extension and spreading events in the Perth Basin, a short distance to the west, are likely to have influenced its evolution. Basement structural trends in the basin indicate an old east-west-trending (?Palaeozoic) fabric that has been overprinted by north-northwesterly oriented Jurassic-Cretaceous extension and wrenching. The resultant structure is complex, particularly where the Palaeozoic and Mesozoic trends intersect. The hydrocarbon potential of the Bremer Basin is currently unknown. However, by analogy with the Eyre Sub-basin, potential source and reservoir sections can be inferred to exist, although the presence of a regional seal and a heatflow regime adequate for the generation of hydrocarbons is less certain. Potential trapping mechanisms for hydrocarbons include wrench-induced anticlines, clastic aprons adjacent to boundary and transfer faults, and stratigraphic traps within dipping Neocomian rocks beneath a major angular unconformity.