In the present study, the concentrations of total mercury in different organs of the Antarctic toothfish (Dissostichus mawsoni) collected from CCAMLR research blocks in Subarea 88.3 and Division 58.4.1 off the coast of Antarctica were determined. The results revealed total mercury concentrations of 0.165 ± 0.095 mg/kg (0.023–0.454 mg/kg) in the Antarctic toothfish. In fish muscle, methylmercury accounted for approximately 40% of the total mercury. In a comparison analysis, muscle and liver tended to bioaccumulate the highest levels of total mercury, and both total mercury and methylmercury contents showed correlations with fish length and weight. Compared with international guidelines, fish contained 2.5–6.4% and 4.0–10.3% of the provisional tolerable weekly intake for total mercury recommended by the Joint FAO/WHO Expert Committee on Food Additives and the tolerable weekly intake for methylmercury proposed by the European Food Safety Authority, respectively. These results suggest that consumption of the Antarctic toothfish presents no health risk to humans.