The Marau deposit is a newly discovered lead-zinc ore deposit in Ketapang of Kalimantan Province in Indonesia. The deposit is distinctly controlled by fissures in the Mesozoic-Cenozoic volcanics. Based on the analyses of mineral assemblages and chemical compositions of ores, the authors is clarified that the ore bodies obviously show a zonation in both horizontal and vertical directions, indicating that the formation of the deposit is related to the hydrothermal alteration, caused by intrusion (injection) of subvolcanic rocks, and the hydrothermal solution is derived from late calc-alkaline volcanic rock formations.