Trace metals may have negative or positive effects on human health. Determination of trace metal levels in muscles of 21 economically important fish, mollusk and crustacean species from Istanbul fish market by ICP-MS was carried out. Trace element contents in seafood species were found to be in the range of 0.081-2.893 mg/kg for Hg, 0.001-2.014 mg/kg for Cd, 0.004-1.096 mg/kg, for Pb, 0.114-28.082 mg/kg for Cu, 3.599-95.671 mg/kg for Zn, 0.028-2.536 mg/kg for As, 0.010-0.598 mg/kg for Co, 1.198-71.169 mg/kg for Al, 0.214-41.810 mg/kg for Mn, <0.001-2.641 mg/kg for Ni, <0.001-3.000 mg/kg for Sri and 0.249-2.912 mg/kg for Cr. The levels of Hg (in 9 species) and that of Cd and Pb (in 2 species) were found to be higher than maximum levels proposed by European legislation. Metal concentrations in the edible parts of seafood, assessed for human uses, were according to provisional tolerable weekly intake (PTWI). The estimated values of mercury metals in muscles of 2 fish, I crustacean and I mollusk species in this study were higher than the established values.