Our study, CAROTID (CAD Randomized Omega-3 Trial In Depression), is a randomized, double-blind, placebo-controlled parallel group trial in persons with CAD who are attending a cardiac rehabilitation program. Patients will receive either omega-3 fatty acids supplements or placebo daily during three months of cardiac rehab. We hypothesize that patients who receive omega-3 fatty acids will show greater improvements in depressive symptoms and quality of life. This research will determine whether there is an antidepressant effect of omega-3 fatty acids in CAD patients undergoing cardiac rehabilitation. If successful, then CAROTID will provide evidence to guide health care providers in the recommendation and use of these supplements.