Abstract The Iglesiente-Sulcis area in southwestern Sardinia is one of the oldest mining districts in the world, with production dating to pre-Roman times. Exploitation in the district was initially for lead-silver-copper deposits and later for zinc and barium deposits. Most of the deposits occur within Lower Cambrian carbonates and, to a minor degree, in Upper Ordovician metasedimentary rocks. The ores can be subdivided into pre-Hercynian (stratiform/stratabound Zn>Pb>Ba) and post-Hercynian (Pb-Ba-Ag-Cu skarn, vein, paleokarst) deposits. The pre-Hercynian deposits have significantly greater economic importance relative to the post-Hercynian ores. Among the Cambrian-hosted ores, a group of variably graded, syngenetic-early diagenetic massive sulfides (pyrite≫sphalerite≫galena) and barite layers are located at the top of the Nebida Group, where there is a transition from terrigenous clastic rocks to shallow water dolomites. Deposition of these metal sulfides is related to onset of strong tensional tectonics during the Cambrian, which also isolated the carbonate platform. A second group of ores, with a greater Pb/Zn ratio and less pyrite, occurs as void-filling, breccia cement and as late diagenetic replacement bodies in lagoonal limestones of the overlying upper Gonnesa Group, below semi permeable calcareous slates of Middle Cambrian age. Economically less significant Ordovician-hosted deposits (Ba≫Pb) are associated with silicification of host rocks. This mineralization occurs as irregular, void fillings and replacement bodies along an angular unconformity between Cambrian carbonates and Upper Ordovician conglomerates and slates. The metals for the pre-Hercynian stratabound ores were derived from a crustal source, with the lead belonging to the same isotopie province as the lead in the mineral deposits of the southern Alps, Austro-alpine nappes, southern France and northern Spain. Sulfur in barite and sulfides is believed to be derived from a marine, variably reduced, lower Paleozoic sulfate source. Strontium in the Cambrian-hosted barite is believed to share similar source rocks. However, Sr in Ordovician-hostcd barite has a much greater range of values, indicating a distinct episode of mineralization. Other than later (syn- to post-Hercynian) remobilization of ores, ore deposits in the southwestern Sardinian district can be regarded as the result of a combination of favorable sedimentary environments with Cambrian and Ordovician-Silurian tensional tectonics. In fact, most ores are enriched along important tectonic lines which controlled the distribution of the sedimentary facies during the Lower Paleozoic. These tectonic lines have been reactivated many times up to the present.