Objectives : We investigated the effects of mountain cultivated ginseng water boiled extract(MCG) on blood glucose and insulin levels, and examined whether lipid metabolism are improved by it in male db/db mice(a murine model of type 2 diabetes mellitus). Methods : 9 weeks old, male db/db mice were divided into 5 groups : C57BL/6J normal, control, MCG-250mg/kg (MCG-1), MCG-500mg/kg(MCG-2) and MCG-1000mg/kg(MCG-3). After mice were treated with MCG for 8 weeks, we measured body weight, food intake, fat weight, visceral organ weight and blood glucose, insulin and lipid levels. Results : 1. We found no difference in body weight, food intake, fat weight and visceral organ weight among the animal groups. 2. Compared with controls, MCG-treated mice had lower blood glucose level and higher blood insulin levels, the magnitude of which was prominent in MCG-2. 3. Compared with controls, MCG-treated mice had lower LDL-cholesterol and higher HDL-cholesterol levels. 4. Compared with controls, MCG-treated mice had blood triglyceride and free fatty acid levels, the magnitude of which was prominent in MCG-2. 5. Blood AST and ALT concentrations were not changed by MCG, indicating MCG do not show any toxic effects. Conclusions : These results demonstrate that MCG effectively increases blood insulin level and decreases blood glucose level, blood lipid levels, and prevents and improves diabetic dyslipidemia and cardiovascular disease.