Mussel samples were collected seasonally from June 2003 to May 2004 from the Istanbul fish markets. Heavy trace metal (Hg, Cd, Pb, Cu, Zn, As, Fe, Co, Al, Mn, Ni, Sn) and macronutrient mineral (Na, K, Mg, Ca, I, Se) concentrations were measured in the muscle of mussel (Mytilus galloprovincialis). The concentrations of heavy metals were determined by using Thermo electron X7 inductively coupled plasma mass spectrometry (ICP-MS). Heavy metal and trace metal content varied with type of seasons. The mean concentrations (mg/kg) of heavy metals in tissues of mussel were as follows: Hg: 0.01-0.16, Cd: 0.75-1.06, Pb: 0.90-1.64, Cu:1.96-3.42, Zn: 68.28-129.94, As:2.68-3.87, Fe:143.49-285.07, Co:0.26-0.39, Al:132.73-264.76, Mn: 1.81-3.87, Ni:1.09-2.06, Sn:0.05-0.11, Na:1020.73-1491.61, K:983.33-1429.24, Mg:404.65-470.19, Ca:664.64-1500.22, I: 1.22-1.74, Se:0.72-0.82. The mercury and copper concentrations are below the limits for mussel proposed by FAO/WHO, EU and Turkish Food Codes and safe within the limits for human consumption in the edible parts of fish species in the region. Especially, for mussel in all season high levels of cadmium, arsenic, zinc were measured for human consumption. It was also found that they were rich in mussel of mineral content, especially Na, K, Mg, Ca, I and Se.