The Mushiston Sn deposit is located in Hercynian South Tien Shan fold and thrust belt on the territory of Tajikistan. Unique features of the deposit include sulphide-dominated composition of the primary ore with stannite being the main ore mineral, and a thick oxidation zone where stannite is replaced by various hydrostannate minerals. Therefore, the Mushiston deposit is a rare example of stannite-cassiterite-hydrostannate mineralization and the type locality where several new hydrostannate minerals such as mushistonite, natanite and vismirnovite were first described. The structure of the deposit is characterized by a series of subvertical, generally NE-trending mineralized veins crosscutting the limbs of the large submeridional anticline composed of Paleozoic sedimentary strata. The primary ore mainly consists of a quartz-stannite group minerals – cassiterite mineral assemblage with other subordinate sulfides and minor sulfosalts. A 200–400 m thick zone of supergene oxidation is developed in the upper part of the deposit. New mineral chemistry data reveal compositional variations of the stannite group minerals, sphalerite and sulfosalts. The chemical compositions of co-existing stannite group minerals and sphalerite indicate extensive mutual substitution between Fe and Zn. The use of stannite-sphalerite geothermometry constrains the temperature for the main stage of the primary ore formation in the range of 257–308 °C. The tetrahedrite geothermometry yields temperatures in the range of 170–200 °C, which is in agreement with geological evidence for the late crystallization of sulfosalts at lower temperatures. The geological and mineralogical features of the Mushiston Sn deposit correspond to the mesothermal hydrothermal vein system mainly developed under intermediate sulfidation conditions. The proposed genetic model for the Mushiston deposit suggests formation of brittle fractures in the thermal aureole above the concealed causative granitoid intrusion, by regional analogue of Permo-Carboniferous age, where magmatic fluids mixed with meteoric water to form the hydrothermal system responsible for deposition of cassiterite-sulfide ore.