Mine drainage at the Namib Lead & Zinc mine in the hyperarid environment of the Namib Desert close to Swakopmund, Namibia, has been investigated using mineralogical, hydrochemical, and isotopic methods. The principal ore minerals are galena and sphalerite. Mine drainage is neutral due to the reactions with the marble gangue rock. Mine water seepage is of the Na-Ca-Cl-SO4 type and sources of dissolved ions are likely halite and gypsum in the unsaturated zone above the mine. Concentrations of dissolved metals are relatively low, and the principal attenuation mechanism of metals is probably their adsorption on ferric minerals because equilibrium of the seepage water with secondary minerals that host the metals is not attained. Based on strongly enriched δ2H (up to 13.27 ‰) and δ18O (up to 4.5 ‰) values, seepage water originates from advective fog and is strongly evaporated after the fog deposition. The high δ13C(DIC) values indicate equilibrium with carbonates and CO2 de-gassing. The δ34S(SO4) values are enriched in shallower depths, probably because of pedogenic gypsum dissolution and then the δ34S values decrease with depth, probably due to the increasing input of sulfur from sulfides. Mine drainage at the Namib Lead & Zinc mine does not represent any risk for the environment due to its neutral character and relatively low seepage water volumes caused by high degree of aridity.