Concentration of magnesium in dorsal ordinary muscles (Dom) obtained from front (Fdom) and rear (Rdom) muscle samples from wild/fattened female/male bluefin tuna (BFT) in the Turkish Eastern Mediterranean were analyzed and compared. A total of 180 individual that is (90 female and 90 male) samples were investigated. Mean Mg levels in the Fdom and Rdom samples of wild and fattened BFT were found to be as follows: 48.76 and 53.20, 52.69 and 40.29 mg 100 g(-1) w wt, respectively. The mean Mg values of the Fdom and Rdom samples of 45 wild and 45 fattened individual female BFT were analyzed and found to be as follows: 51.31 and 55.09, 56.46 and 42.33 mg 100 g(-1) w wt, respectively. The parameters for the Fdom and Rdom of 45 wild and 45 fattened male specimens were determined to be 46.12 and 51.40, 48.92 and 38.26 mg 100 g(-1) w wt, respectively. Both wild/fattened fish, Mg differences in the Fdom and Rdom tissues and the differences in levels of Mg in the Fdom and Rdom samples of wild vs. fattened female and male samples were significant (p < 0.05).