The ginseng root has been used as a tonic remedy, and its antidiabetic activity has been demonstrated as early as 1920s. Although wild ginseng was anecdotally thought to be superior to cultivated ginseng in terms of pharmacological properties, there have been no prior reports on its improvement of metabolic syndrome. In this study, we figured out whether wild ginseng ethanol extract (WGEE) exerted the preventive effects on high fat diet-induced metabolic syndrome as well as treatment effect in ICR mice. In the preventive mode experiment, WGEE at 500 mg/kg significantly inhibited body weight gain $(16\%)$, fasting blood glucose $(37\%)$ and insulin $(37\%)$, triglyceride $(15\%)$, and free fatty acid levels $(32\%)$ when compared to those in high fat diet (HFD) fed control group. WGEE-treated mice at doses of 250 and 500mg/kg improved the insulin resistance index by $55\%;and;61\%$ compared to the HFD control group, respectively. In the treatment mode experiment, WGEE also markedly reduced the blood glucose levels (210 mg/dl in control group was lowered to 167 mg/dl).Taken together, WGEE has potential as a preventive and treatment agent for metabolic syndrome and deserves clinical trial in the near future.