Total mercury and methylmercury concentrations were measured in sediments and marine organisms from the Taranto Gulf to understand their distribution and partitioning. Sediment concentrations ranged from 0.036 to 7.730mg/kg (mean: 2.777mg/kg d.w.) and from 1 to 40μg/kg (mean: 11μg/kg d.w.) for total mercury (THg) and methylmercury (Me–Hg), respectively. In mollusks THg ranged from n.d. to 1870μg/kg d.w. while in fish from 324 to 1740μg/kg d.w. Me–Hg concentrations in fish ranged from 190 to 1040μg/kg d.w. and from n.d. to 1321μg/kg d.w. in mollusks. THg exceeded the maximum level fixed by the European Commission (0.5mg/kg w.w.) only in gastropod Hexaplex t. The calculated weekly intake was in many cases over the Provisional Tolerable Weekly Intake established by EFSA for all edible species. These results seem to indicate that dietary consumption of this seafood implicates an appreciable risk for human health.