Patients with increased triglyceride levels compared to those with normal levels are at higher risk for coronary heart disease. In patients with severe (≥500 mg/dl) hypertriglyceridemia (SHTG), clinical trials have demonstrated that prescription ω-3 fatty acids (P-OM3s) 4 g/day can decrease triglyceride levels by 45%. However, the precise health and economic benefits of decreasing SHTG with P-OM3 are unknown. We used the previously validated Archimedes model to simulate a 20-year trial involving subjects 45 to 75 years old with SHTG. The trial consisted of an intervention arm (P-OM3 4 g/day) and a control arm. Simulation results for the control arm indicated that subjects with SHTG are at about 2 times higher risk for myocardial infarction than those with normal triglyceride levels. Using estimates from previous epidemiologic studies and meta-analyses with OM3s, the model predicted 29% to 36% decreases in various measurements of adverse cardiac events for the intervention arm. The model also predicted a decrease in ischemic stroke of 24% (95% confidence interval 15 to 33). For the 20-year simulated trial, the cost per quality-adjusted life-year gained for the currently available P-OM3 approved by the Food and Drug Administration was $47,000. Results remained robust under different clinical assumptions. In our model P-OM3 was effective in decreasing triglyceride levels and cardiovascular disease risk in patients with SHTG. In conclusion, P-OM3 medication is cost effective in our simulated trial and comparable to other cost-effective cardiovascular interventions.