The investigators propose to conduct a placebo controlled, double blind, parallel group randomized trial to evaluate the efficacy of Lovaza (formerly known as Omacor) in reducing triglyceride levels in youth ages 10-19 years old whose baseline triglycerides range from150 mg/dl to 1000 mg/dl. Seventy subjects will be recruited at baseline and randomized to the treatment condition, Lovaza 4 grams/day for 6 months or the control condition, a corn oil placebo, 4 tablets a day for 6 months. Participants in both the treatment and control groups will receive the standard of care, which is dietary advice to follow a low, refined carbohydrate and low saturated fat diet that emphasizes increasing intake of fruits and vegetables and eating 2 servings per week of fishes rich in omega-3 fatty acids, consistent with the American Heart Association recommendations (Kris-Etherton, 2003). Subjects will be randomized to the treatment or control condition after a 4 week run-in period of dietary education and advice. The primary outcome will be change in fasting triglycerides from baseline to 3 months.