Beneficial effects of peroxisome proliferator-activated receptor alpha (PPAR alpha) agonists have been reported in improving insulin sensitivity and raising serum total adiponectin. High molecular weight (HMW) adiponectin, which is secreted from adipocytes, and visfatin, which is also expressed in adipose tissue, is related to glucose metabolism. In view of the additive effects of PPAR alpha agonists on these adipocytokines and glucose metabolism, we investigated male hypertriglyceridemic subjects who were treated with fenofibrate. Eleven male subjects with hypertriglyceridemia were treated with fenofibrate and serum total cholesterol (T-cho), triglyceride, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), fasting glucose, fasting insulin, total and HMW adiponectin, and serum visfatin levels were determined before and 3 months after treatment. Fenofibrate treatment significantly lowered T-cho, triglyceride, and LDL-C levels. There was a statistically significant increase of HDL-C. No differences in insulin sensitivity indices (G/I ratio and HOMA-IR) were observed between before and after treatment with fenofibrate. The treatment did not alter the levels of serum total adiponectin and visfatin in the hypertriglyceridemic patients, while serum HMW adiponectin increased significantly. This study demonstrates that fenofibrate increases serum HMW adiponectin levels, whereas visfatin is not regulated by fenofibrate in hypertriglyceridemic subjects. Further investigations are warranted to determine whether the elevation of HMW adiponectin caused by fenofibrate might improve insulin sensitivity.