The South Australian part of the Cooper Basin had been under licence continuously since 1954, however on 27 February 1999 Petroleum Exploration Licences (PELs) 5&6 expired. The former PEL 5&6 area is being released in four bidding rounds over 1998?2000, with a planned total of 27 blocks on offer for the first three rounds. The first round commenced in October 1998 when eleven blocks flanking the Cooper Basin (CO98-A to K) were released. Applications for those blocks closed on 11 March 1999 and a total of 41 bids were received from 15 consortia. This keen bidding resulted in 11 exploration licences being offered to 6 consortia who will invest a total of $45 million during the next 5 years. The second round of eight core Cooper Basin blocks (CO99-A to H) in the Patchawarra Trough was released in April 1999 (Fig. 1). Applications for these blocks closed on 25 November 1999 and a total of 47 bids were received from 16 consortia. This has resulted in 8 exploration licences being offered to 7 consortia who will invest a total of $120 million during the next 5 years. The current release of eight Cooper Basin blocks (CO2000-A to H) comprising four outer blocks in the Patchawarra Trough, one outer block to the west of the Wooloo Trough and three inner blocks adjacent to producing oil and gas fields, forms the third round acreage release (Fig. 1). The total area on offer is approximately 12 735 km2 or 3 147 000 acres (Table 1). A six month evaluation period applies for blocks CO2000-A to E blocks with applications closing at 4.00 pm on Thursday 29 June 2000 whilst a nine month evaluation period applies for blocks CO2000-F to H with applications closing at 4.00 pm on Thursday 28 September 2000.