AbstractKayu kuning has already used as traditional medicine to treat various disease. The aim of this study was to evaluate the in vitro antioxidant and antidiabetic activity of hexane, ethyl acetate, and methanol extract of Kayu kuning leaves. The antioxidant activities of the Kayu kuning extracts were measured by 2, 2-diphenyl-1-picrylhydrazyl (DPPH), superoxide radical, and hydroxyl radical assays. The antidiabetic activity was evaluated by α-amylase and α-glucosidase inhibition assays. Compared with the standard vitamin C, extract hexane, ethyl acetate, and methanol of Kayu kuning shown potent as antioxidant. The methanol extract showed highest scavenging activity on superoxide and hydroxyl radical. The ethyl acetate extract showed highest scavenging activity on DPPH radical. Compared with the standard acarbose, extract hexane and ethyl acetate of Kayu kuning shown potent as antidiabetic while the methanol extract had no potent. The ethyl acetate extract showed highest potent as antidiabetic.