We previously evaluated the effect of a s-glucan fraction, a major component of soluble dietary fiber, from barley (barley gum) on lipid metabolism in experimental animals. There are very few reports on the influence of dietary fiber from barley on the parameters of metabolic syndrome in Japanese subjects. Therefore, we investigated whether the intake of high-s-glucan barley modifies parameters in hypercholesterolemic Japanese men. We found barley intake significantly reduced serum concentrations of total and LDL-cholesterol during the trial. In addition, significant reductions were observed in visceral fat, body mass index, and waist circumstance at the experimental end point. We also investigated the effects of barley on the parameters of metabolic syndrome in diet-induced obese mice: barley intake significantly reduced the mass of retroperitoneal fat, the size of adipocytes in abdominal fat tissues, and liver lipid accumulation. Glucose tolerance test results suggested barley intake attenuated the progression of insulin intolerance. Modification of insulin sensitivity suppressed sterol regulatory element binding protein-1c (SREBP-1c ) mRNA expression and also suppressed lipogenic enzyme mRNA expression which is under the regulation of SREBP-1c.