AIM: The Mudlankie Seismic Survey was the first extensive survey using the Vibroseis method to be carried out over a wide area of the southwestern Cooper Basin, and was designed: (1) to augment the mapping of existing fields and improve their structural and stratigraphic definition; (2) to delineate new structures in areas of high potential near existing fields, particularly in areas having thick, good quality hydrocarbon reservoirs, where smaller structures may now be viewed as being potentially commercial; and (3) to better define the northwestern extent of Gidgealpa Group sediments by adding reconnaisance lines to the programme. METHODS: Survey dates: 1/5/73 - 5/10/73. Energy source: Vibroseis. CDP coverage: 1200% (except 600% over lines EAD, EAE, EAF, EAJ, EAK and EAL. Recording mode: 24 channel digital - Leach amplifier/Globe 9 track recorder. VP interval: 440 feet, group interval: 330 feet. 64 new lines totalling 390.5 miles of 12-fold plus 69.6 miles of 6-fold data, ranging over five separate farmin areas held by different exploration consortia, were acquired for Delhi by SSL Party 651 and processed by SSL in Adelaide. RESULTS: The Mudlankie survey has demonstrated that the Vibroseis source technique, combined with a high degree of trace multiplicity plus binary gain digital recording and processing, now provides much more structural and stratigraphic information from below Horizon 'P' than was obtained by most previous seismic surveys in the southwestern Cooper Basin area. Besides defining some small new structures and providing better detail on a number of established ones (e.g. Beantree, Swan Lake, Packsaddle, Bookabourdie, Nappacoongee, Moomba and Dullingari), the survey has shown that better definition of potential combined structural/stratigraphic traps on the flanks of major structural highs may now be possible, i.e. the Packsaddle SE flank Permian onlap/truncation lead ('Pondrinie'), the Della SW flank fault closed lead ('Marabooka'), and other potential Permian pinchout leads indicated on the basin margin northwest of Fly Lake/Moorari.