The granites of the Goiás Tin Province (GTP) are distributed in four subprovinces in the south-central state of Goiás: Rio Tocantins (RT), Rio Paraná (RP), Pirenópolis-Goianésia (PG) and Ipameri (IP). The tin granites are intrusive in the Granite-gneiss Complex (Archaean?) and in the Tincunzal Formation (Early Proterozoic), and outcrop among Middle Proterozoic metasediments. Massifs of the western subprovinces (RT, PG, IP) are situated in the inner part of the Uruaçu Fold Belt and are surrounded by strongly deformed sediments metamorphosed in amphibolite or upper greenschíst facies. Eastern subprovince (RP) massifs occur in the outer part of this belt, domain of weakly metamorphosed and deformed Araí Middle Proterozoic sediments. Tin granites of the RT and RP subprovinces differ in structure, texture and metalogenesis. The former (Serra da Mesa Type) consíst of strongly deformed ellipsoidal bodies of batholitic dimensions and display a conspicuous border folíation, similar to mantled domes. RP Subprovince by granites (pedra Branca Type) are weakly deformed by subvolcanic plutons. All granític bodies are dominantly biotite granities, sometimes muscovitízed, with a very restricted hornblende fades in the RT Subprovince. Post-magmatic changes like albitization and greisenization are very common and associated tin deposits occur in albitites, biotites, greisenized granites, exo and endogreisen, pegmatites, and quartz veins. Common associatíons are: 1) cassiterite-tantalite-columbite-wolframite in albitized granites and pegmatites in the west and 2) cassiterite-fluorite-sulphídes in the east. Goiás tin granites are predominantly peraluminous with an alkaline trend in the western types. Ali of them are correlate with A- or S-type granites and are similar to some tin granites of the Amazon Craton. Granites of the Ilmenite Series are represented by non-altered biotite granites whereas hydrothermally altered granites represent the Magnetite Series. Rare earth element (R.E.E.) signatures are characteristic of tin granites. Biotite granites, albitized granites, and greisen as well as rhyolites of the base of Middle Proterozoic metassediments have the same REE pattern, with strong negative Europium anomalíes. Geochronological data indicate ages between 1,650-1,800 Ma in the western granites (Serra da Mesa Type) and 1,400 Ma in the eastern examples (Pedra Branca Type).The granites of the Goiás Tin Province (GTP) are distributed in four subprovinces in the south-central state of Goiás: Rio Tocantins (RT), Rio Paraná (RP), Pirenópolis-Goianésia (PG) and Ipameri (IP). The tin granites are intrusive in the Granite-gneiss Complex (Archaean?) and in the Tincunzal Formation (Early Proterozoic), and outcrop among Middle Proterozoic metasediments. Massifs of the western subprovinces (RT, PG, IP) are situated in the inner part of the Uruaçu Fold Belt and are surrounded by strongly deformed sediments metamorphosed in amphibolite or upper greenschíst facies. Eastern subprovince (RP) massifs occur in the outer part of this belt, domain of weakly metamorphosed and deformed Araí Middle Proterozoic sediments. Tin granites of the RT and RP subprovinces differ in structure, texture and metalogenesis. The former (Serra da Mesa Type) consíst of strongly deformed ellipsoidal bodies of batholitic dimensions and display a conspicuous border folíation, similar to mantled domes. RP Subprovince by granites (pedra Branca Type) are weakly deformed by subvolcanic plutons. All granític bodies are dominantly biotite granities, sometimes muscovitízed, with a very restricted hornblende fades in the RT Subprovince. Post-magmatic changes like albitization and greisenization are very common and associated tin deposits occur in albitites, biotites, greisenized granites, exo and endogreisen, pegmatites, and quartz veins. Common associatíons are: 1) cassiterite-tantalite-columbite-wolframite in albitized granites and pegmatites in the west and 2) cassiterite-fluorite-sulphídes in the east. Goiás tin granites are predominantly peraluminous with an alkaline trend in the western types. Ali of them are correlate with A- or S-type granites and are similar to some tin granites of the Amazon Craton. Granites of the Ilmenite Series are represented by non-altered biotite granites whereas hydrothermally altered granites represent the Magnetite Series. Rare earth element (R.E.E.) signatures are characteristic of tin granites. Biotite granites, albitized granites, and greisen as well as rhyolites of the base of Middle Proterozoic metassediments have the same REE pattern, with strong negative Europium anomalíes. Geochronological data indicate ages between 1,650-1,800 Ma in the western granites (Serra da Mesa Type) and 1,400 Ma in the eastern examples (Pedra Branca Type).