Red yeast rice has many biological activities such as antihyperglycemic, antihypercolesterolemic, antidiabetic and antioxidant. This study was conducted to search for the most active extracs of red yeast rice as an in vitro antidiabetes. Antidiabetic activity was measured through α-glucosidase inhibition assay. Samples were ethanol 95% extract of red yeast rice, as well as its fractionated products using n-hexane, dicloromethane, ethyl acetate and water. Extraction of red yeast rice powder with 95% ethanol had a yield of 9.44%. The yield from fractionation of ethanol 95% extract using n-hexane, dicloromethane, ethyl acetate and the water were 1.99%, 1.13%, 0.59% and 1.36% respectively. The phytochemical test showed that ethanol 95% extract of extract contained flavonoids, alkaloids and saponin. The highest antidiabetic activity was shown by ethanol 95% extracts with IC50 value of 20.86 μg/ mL and exhibited an uncompetitive inhibition. Therefore, red yeast rice extracts is potential for antidiabetes.