Depressive disorders are common in patients with Coronary Artery Disease (CAD), occurring in up to 47% of patients. Left untreated, these symptoms not only have a strong negative impact on quality-of-life, but also increase risk of future cardiac events and death. Unfortunately, about 64% of CAD patients do not respond to current antidepressant treatments. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are two omega-3 (ω-3) fatty acids found in fatty fish that are important for brain function. Recent evidence showed that depressed CAD patients have lower levels of EPA and DHA than non-depressed CAD patients. This information, taken together with the known roles of ω-3 fatty acids in brain function, suggests that deficiencies may contribute to depression. However, it is unknown if increasing consumption of ω-3 fatty acids would alleviate depression and improve quality of life. While intake of adequate levels of ω-3 fatty acids is difficult to obtain through diet, concentrated supplements containing EPA and DHA that are safe, readily available, and inexpensive are now obtainable in Canada. CAROTID (CAD Randomized Omega-3 Trial In Depression) will randomize patients with CAD, with and without depressive symptoms, after 6 months of cardiac rehabilitation and usual care to receive either ω-3 fatty acid supplements or placebo daily during their final 6 months of cardiac rehabilitation. The investigators hypothesize that CAD patients randomized to receive ω-3 fatty acid supplements will show greater improvement in depressive symptoms and quality-of-life over time. The investigators will also evaluate possible improvements in other important determinants of quality of life: memory and other cognitive abilities.