Mahour polymetal deposit located west of Nehbandan, east-central Iran, formed in hypabyssal acid rocks. Mineralization occurs along a three-km-long vein. Three zones have observed in the ore, downward: 1) leached zone marked by malachite, azurite, hematite, goethite and limonite, 2) supergene zone characterized by bornite, covellite, and chalcocite, and 3) Hypogene zone containing magnetite, chalcopyrite, pyrite, galena, and sphalerite. The significant alterations are silicic, sericitic, and propylithic. Gangue minerals are mainly composed of quartz and calcite. The textures vary from replacement and open-space filling to brecciate. Fluid inclusion study of three samples of sphalerite is indicative of temperature variation of the ore-forming fluids between 194°C and 292°C. Considering the measured ice-melting temperature (T_m ice), the salinity is estimated to be between 11.7 and 23 equivalent weight of NaCl (wt%). Mineralogical and fluid inclusion evidence such as texture and structure of mineralization, vein mineralization, mineral paragenesis, gangue minerals, wall-rock alteration, homogenization temperature and salinity and trapped fluids, and depth of mineralization, all suggest that the Mahour deposit is a vein-type epithermal to mesothermal deposit.