Carbonate replacement Pb-Zn-Ag deposits (CRDs) in the Lavrion district are spatially related to an Upper Miocene granodiorite intrusion and various sills and dikes of intermediate to acid composition. The mjneralogy of CRDs includes base-metal sulphides as well as sulphosalts containing Ag, Bi, Sn, Sb, As, and Pb, particularly at Plaka and Kamariza. Fluid inclusion studies suggest the CRDs were deposited from moderate-temperature {132°-365°C), CO2-poor, and low- to moderately-saline (I to 20 wt% NaCl equivalent) fluids. Sulphur isotope compositions of sulphides and sulphates suggest a magmatic contribution to the ore fluids and a marine seawater origin for barite. Carbon and oxygen isotope compositions of calcite intergrown with sulphides reflect variable exchange of the ore-bearing fluid with the upper and lower marble host and with proximity to the Plaka granodiorite. The CRDs resemble carbonate-hosted sulphide deposits in Mexico, central Colorado, and northern Greece.