One of the most widely eaten fishes worldwide is tuna. While it is rich in protein, low in fat and calories and is an excellent source of the essential omega-3 fatty acids which help to lower blood pressure and cholesterol, the mercury content of canned tuna can pose great health risk for those who consume them often. In this study, mercury was determined after digestion by the standard methods of Association of Official Analytical Chemists. Mercury contents of canned tuna were determined by cold vapor atomic absorption spectrophotometer. The metal content, expressed in μg/g wet weight for mercury varied with an average of <0.0003, 0.0421 and <0.0003 in canned tuna A, B and C, respectively. The values were comparable and in the range of the literature values. The results of this study indicate that canned tuna fish manufactured and sold in Philippines have concentrations below the standards of WHO for this toxic metal.