This report was compiled as a draft document in 1997 by Senior Geologist Jeff Valentine, a former officer working in the then Mineral Resources Branch, Department of Mines and Energy, South Australia, and thereafter was put aside and disregarded by Departmental staff until its recent discovery and subsequent completion. The now completed report details the 84 major gypsum deposits known in South Australia, and provides their name, locality, tenure, geology, production/grade, assay, resource, operational, history and reference data. 39 of the deposits have recorded past production, and 14 of them are still currently producing. 35 deposits have known gypsum reserves awaiting future production, of which Lake MacDonnell has the largest reserve of about 600 Mt. Deposit tenure and production details have recently been upgraded to include the period from 1997 to 2015, and records for individual gypsum deposits not listed in the original 1997 draft, or which were discovered post-1997, have also been added. The gypsum resources of South Australia, including the early history of gypsum mining in South Australia, have been previously recorded by Jack (1921), Willington (1952) and Valentine (1989). The earliest recorded gypsum production in South Australia was in 1874 from lakes located at the lower end of Yorke Peninsula, and led to the commercial production of gypsum for plaster manufacture at Marion Lake and Lake Fowler. In the early 1900s, flour gypsum that occurs in the Riverland was used locally as fertilizer and soil conditioner. In 1919, production commenced at Lake MacDonnell on Eyre Peninsula, from where the gypsum was shipped to Sydney for the manufacture of plaster and allied products. The Lake MacDonnell deposit developed into the State’s and Australia’s largest gypsum mining operation, and is still SA's largest producer, accounting for about 90% of the State’s production. The gypsum is railed 70 km to port facilities at Thevenard for shipment interstate and overseas. In the early 1900s, Plaster of Paris began to be produced locally from raw SA gypsum, and plaster-making plants were established at Hindmarsh and Birkenhead in Adelaide, at Stenhouse Bay on Yorke Peninsula, and at Thevenard on north-western Eyre Peninsula. Production levels were small, around a few hundred tonnes annually, the bulk of the plaster being exported interstate. Currently, about 68% of SA's gypsum production is used around the nation for making builder's plaster board, 22% for cement manufacture, and 10% for agricultural purposes. To date, South Australia has produced a total of about 75 Mt of gypsum, and remaining resources are estimated at about 800 Mt.