The present invention provides highly purified omega-3 fatty acid formulations. Certain formulations provided herein have contain greater than 85% omega-3 fatty acids by weight. Certain other formulations provided herein contain EPA and DHA in a ratio of from about 4.01:1 to about 5:1. The invention also provides methods of using the dosage forms to treat a variety of cardiovascular, autoimmune, inflammatory, and central nervous system disorders by administering a formulation of the invention to a patient in need thereof.