A combined EM, resistivity and seismic refraction survey was carried out in the Great Artesian Basin near Lake Eyre South between 18.9.86 and 8.10.86. 15 vertical electrical soundings, 12 Sirotem traverses (150 readings) and 7 refraction spreads were recorded. This survey forms part of the second phase of a 5-year detailed study of the hydrogeological regime of the Great Artesian Basin, which commenced in 1985. The survey tested the ability of combined, cost effective geophysical techniques to detect the basal Cretaceous aquifer and the Precambrian bedrock as an alternative to the more expensive high resolution seismic reflection technique.