The effect of chlorine dioxide (ClO 2 ) treatment on nutrients of seafood was studied using Atlantic salmon (Salmo salar) and red grouper (Epinephelus morio) with five volumes (1:5, w/v) of aqueous ClO 2 at 20, 40, 100, and 200 ppm ClO 2 in 3.5% brine for 5 min. Compared to nontreated controls, treatment of salmon and red grouper with ClO 2 solutions in brine did not significantly change the contents of protein, fat, moisture, niacin, calcium, iron, phosphorus, or potassium. However, such treatment with brine or ClO 2 solutions in brine caused a significant reduction in thiamin content in both species, but only riboflavin was reduced significantly in red grouper, possibly due to the solubilization effect of salt on the vitamins.