Background : Black ginseng is known to be effective product made with ginseng. In general, most black ginseng is manufactured by high teperature condition (90 - 95℃). However this temperature condition may not be optimal to obtain ginsenoside components beneficial for inhibition of diabetes. Here, we examined anti-diabetic effect of black ginseng manufactured by low low temperature process. Methods and Results : For diabetes induction, ICR mice were intraperitoneally injected with alloxan (50 ㎎/㎏). Mice were administered orally with 1 or 3 ㎎/mouse of the extract of black ginseng (BG-L) manufactured with low temperature (80℃), and its anti-diabetic effect was evaluated by measuring the level of glucose in blood. The consecutive administration of BG-L extract resulted in a significant decrease of glucose. In oral and intravenous glucose tolerance test (OGTT and IVGTT, respectively), administration of BG extract significantly reduced the level of glucose in blood within 20 min after glucose treatment. And its suppressive effect on glucose tolerance was effective not only pre-treatment but also post-treatment of BG extract. Oral administration of BG extract enhanced the level of insulin in blood, and decreased the amount of water consumption in alloxan-induced diabetic mice 5 days after alloxan treatment. In addition, BG-L significantly inhibited the level of blood glucose in db/db type-II diabetic mice. Conclusion : These results suggest that the black ginseng extract manufactured manufactured with low temperature (80℃) is a promising candidate applicable to the development of anti-diabetic nutraceutical foods and drugs.