Abstract: The Instranca Massif is underlain by a basement of gneissic rocks unconformably overlain by a coverof Paleozoic and Mesozoic sedimentary rocks. These rocks are composed of shale, limestone and sandstone which areregionally metamorphosed in the greenschist facies. The sedimentary rocks are, in turn, largely intruded by UpperCretaceous granodioritic rocks and in part covered by volcano - sedimentary rocks also of Upper Cretaceous age.The many ore deposits and mineralizations known from the Istranca Massif generally occur in the contactzone between the intrusive and sedimentary cover rocks; they are the result of hydrothermal contact mineralization.Disseminated and stockwork types of mineralization formed by primary ore minerals such as pyrite, some chalcopyrite,traces of molybdenite and scheelite are found close to the contact zone within the granodiorite porphyry; locally,hydrothermal quartz veins containing trace of molybdenite cut the granodiorite porphyry. The more important deposits and mineralizations occur in some contact zones; they consist of primary ore minerals, the most important ofwhich are magnetite, chalcopyrite, bornite, the fahlerz group, pyrite, pyrrhotite, the Bi-minerals (e.g., bismuth, bismuthinite, emplectite, wittichenite, gladite, tatradymtte, etc.), sphalerite, cubanite, valleriite and scheelite in association with such secondary ore minerals as chalcocite, coveilite, malachite, azurite and limonite.The paragenesis and the texture and structure of the öre minerals has been studied in detail. The mineral cubanite and valleriite indicate a temperature of formation of 250° - 300°C, elsewhere mineralization generally occurs insome skarn zones where chalcopyrite contains exsolution stars,of sphalerite; these phenomena show that these ore deposits and mineralizations have been formed in meso - katathermal conditions.One of the most important ore deposits in the Istranca Massif is ikiztepeler, which was being worked for Cu,Mo and W.