In this study, the effects of seasonal and sexual differences on the nutritional composition, macro (Na, Mg, P, K, Ca), trace element (Mn, Fe, Co, Cu, Zn, Mo, Ni, Se) and potential toxic metal levels (Cd, Pb, As) of horse mackerel (Trachurus trachurus) caught in the middle Black Sea coast during all seasons were investigated. The metal levels of muscle tissues of the examined specimens were determined using ICP-MS instrument. The results showed that horse mackerel had a high nutritional value in terms of protein and lipid levels. Metal levels were found to be different in terms of sexual and seasonal factors. With regard to macro element levels, horse mackerel muscle was found to be rich. Zn and Cu levels of the trace elements were below the legal limits specified by the codex. It was also observed that the levels of Cd and Pb in horse mackerel muscle tissue were below the FAO (Food Agriculture Organ U N 464:5-10, 1983) limit values and above the TFC (Turkish Food Codex 2011) limit values. In terms of EWI and EDI values, horse mackerel was found to be non-toxic. This study suggests that horse mackerel is beneficial seafood for human health and nutrition.