The Coxco deposit is a stratabound lead-zinc deposit which shows many similarities to Mississippi Valley-type orebodies. This particular deposit is one of several similar orebodies in the McArthur River district. Ore mineralization is contained within several dolomitic units deposited in a sedimentary sequence in a broad, intracratonic basin. The local area underwent alternating periods of subsidence and uplift which resulted in numerous, recognizable palaeoerosional surfaces. Within the dolomitic units, stage I mineralization consists of fine-grained sphalerite, galena and other sulphides deposited in karst-produced solution cavities. Mineral formation resulted from precipitation of metal-sulphur rich solutions at low T (<100oC). Stage II mineralization of coarsely crystalline sulphides occurs as veins and as matrix for dolomitic breccias. Temperatures of ore formation from solutions during this stage are estimated to be in the range of 100o-170oC. A genetic model of ore formation is presented relating regional geology, local environment of mineralization, isotopic data, and the inferred source of the ore constituents. This deposit is compared with others in the area and with Mississippi Valley-type deposits in general.-J.E.S.