Supramonte is one of the biggest and interesting karst areas of Sardinia (Italy), hosting extensive cave systems explored since the 50s. Early cavers and scientists have carried out some dye tests, but hydrogeological research was hindered by lack of ac­cessible underground rivers. A complex subterranean river sys­tem has been discovered in the past decade enabling to organ­ise several new tracer tests. The history of cave explorations, the morphology and hydrology of the systems and the dye tracing experiments are reviewed in this paper in order to give an up­dated view on hydrogeology of this important karst area.