Sudden death is one of the most common modes of death in those who survive a myocardial infarction. A recent study of 11,324 patients showed a marked decrease in risk of sudden cardiac death as well as a reduction in all-cause mortality in the post-myocardial infarction group taking a highly purified form of omega-3 fatty acids, added to the use of other secondary prevention drugs, including b-blockers and lipid-lowering therapy. There is now amounting evidence indicating that the clinical benefits of highly purified omega-3 fatty acids may be attributed to their anti-arrhythmogenic properties. Evidence for this mechanism of benefit is reviewed here.