This study investigated whether increased adiposity is prevented by estrogen replacement in female ovariectomized (OVX) C57BL/6J mice, an animal model of human menopause and whether these metabolic changes reflect the inhibitory action of estrogen on peroxisome proliferator-activated receptor $gamma$ ($PPAR{gamma}$)-regulated gene expression. Treatment of $17{eta}$-estradiol for the last one week of the experiment decreased high fat diet-induced body weight gain and white adipose tissue mass compared to OVX control mice. Histological analysis showed that administration of $17{eta}$-estradiol to mice decreased the size of adipocytes in parametrial adipose tissue versus OVX control mice. In addition, $17{eta}$-estradiol reduced the adipose expression of $PPAR{gamma}$ as well as $PPAR{gamma}$ target genes such as adipocyte fatty acid binding protein and tumor necrosis factor $alpha$. These results suggest that $17{eta}$-estradiol may inhibit adiposity through reducing the $PPAR{gamma}$ activities in female OVX mice.