We hypothesized that fattening Wagyu cattle fed conventional low-vitamin fattening diets are exposed to oxidative stress. In this experiment, we studied the plasma concentrations of 8-isoprostane and the fat depot-specific effects of the diet-induced adipogenic (C/EBPβ, C/EBPδ, C/EBPα and PPARγ2) and adipokine (VEGF, FGF-2, leptin and adiponectin) gene expressions in fattening Wagyu steers. Animals were fed a high-vitamin (α-tocopherol and β-carotene) diet (HV) or a control diet (CT) during the fattening period (from 10 to 30 months of age). The plasma concentrations of 8-isoprostane, a marker of oxidative stress, were significantly lower in the HV group than in the CT group. In mesenteric adipose tissue, the expressions of the adipogenic and adipokine genes in the HV group were significantly lower than those in the CT group. In contrast, there were no differences in the expression of the adipogenic and adipokine genes in subcutaneous adipose tissue between groups. These results suggest that higher intake of dietary α-tocopherol and β-carotene affects the expression patterns of adipogenic and adipokine genes in a fat depot-specific manner with the reduction of plasma 8-isoprostane concentrations.