We determined the ability of in-trial measurements of triglycerides (TGs) to predict new cardiovascular events (CVEs) using data from the Incremental Decrease in End Points through Aggressive Lipid Lowering (IDEAL) and Treating to New Targets (TNT) trials. The trials compared atorvastatin 80 mg/day with moderate-dose statin therapy (simvastatin 20 to 40 mg/day in IDEAL and atorvastatin 10 mg/day in TNT) in patients with clinically evident coronary heart disease or a history of myocardial infarction. The outcome measurement in the present research was CVE occurring after the first year of the trial. After adjusting for age, gender, and study, risk of CVEs increased with increasing TGs (p <0.001 for trend across quintiles of TGs). Patients in the highest quintile had a 63% higher rate of CVEs than patients in the lowest quintile (hazard ratio 1.63, 95% confidence interval 1.46 to 1.81) and the relation of TGs to risk was apparent even within the normal range of TGs. The ability of TG measurements to predict risk decreased when high-density lipoprotein cholesterol and apolipoprotein B:apolipoprotein A-1 were included in the statistical analysis, and it was abolished with inclusion of further variables (diabetes, body mass index, glucose, hypertension, and smoking; (p = 0.044 and 0.621, respectively, for trend across quintiles of TGs). Similar results were obtained in patients in whom low-density lipoprotein cholesterol had been lowered to guideline-recommended levels. In conclusion, even slightly increased TG levels are associated with higher risk of recurrence of CVEs in statin-treated patients and should be considered a useful marker of risk.