Background. Fenofibrate, a peroxisome proliferator-activated receptor-α (PPARα) agonist, is used to treat patients with hypercholesterolemia and hypertriglyceridemia in order to reduce the risk of development of the atherosclerotic cardiovascular disease. However, it exerts pleiotropic effects beyond correcting atherogenic dyslipidemia to treat hypercholesterolemia. Objectives. The aim of this study was to investigate the potential effects of fenofibrate on endothelial function by analyzing the serum nitric oxide (NO) levels in patients with hypertriglyceridemia. Material and methods. Lipid profiles and serum NO levels were assessed in 56 healthy adults aged 29 to 84 years, before and after 12 weeks of fenofibrate (250 mg/d; n = 30) or placebo (n = 26). Appropriate dietary suggestions for hypertriglyceridemia were made for all patients. This study was randomized, double-blind and placebo-controlled in design. Results. Total cholesterol, low-density lipoprotein (LDL), very low-density lipoprotein (VLDL) and triglyceride levels significantly decreased; high-density lipoprotein (HDL) and NO levels significantly increased after 12 weeks of fenofibrate therapy. We observed a statistically significant correlation between the increase in serum NO levels and decrease in serum triglyceride levels (r = -0.42, p = 0.02) in the fenofibrate group. Conclusions. The positive effect of short-term fenofibrate treatments on vascular endothelial functions in patients with hypertriglyceridemia has been demonstrated by increasing the serum NO levels. Agents such as fenofibrate targeting PPARα-associated signaling pathways show promise as an alternative treatment of vascular dysfunction related to advanced age and hyperlipidemia.