The smelting copper slags from the archaeological sites of Transacqua and Segonzano in Trentino (Italy) were fully analysed to study the extraction of copper from copper and iron sulphide minerals that were carried out in the southeastern Alps during the Late Bronze Age. A combined approach involving physical, chemical, mineralogical and petrographic analyses was applied on over 130 copper slags from Transacqua and Segonzano. Three different types of slags were distinguished from the mineralogical and chemical points of view, differing in the size and relative amount of the unreacted sulphides and matte, the size of metallic copper prills, the ratio between unreacted quartz and newly formed silicate phases and viscosity. By combining all the observations, it is suggested that the three types of slags are the product of a Cu-smelting process formed by three main operations: slagging, matting and refining, which were standardised in the southeast Alps between the fourteenth and the eleventh century BC.