Type 2 diabetes mellitus (T2DM) is one of the most common degenerative disorders. For therapeutic use, herbs are commonly used in Indonesia for T2DM treatment, one of them is (Cosmos caudatus) kenikir's leaves. In previous studies, kenikir's leaves have high antidiabetic and antioxidant activity. However, a comparison of antidiabetic activity from many extracts of kenikir's leave is remain unclear. This study will compare the antidiabetic and antioxidant properties of various kenikir's leave extract. Kenikir's leaves are extracted by maceration methods for three days using three different solvents: boiling water, 50% ethanol, dan ethanol 100%.Then, phenolic and flavonoid content will be measured, as well as antioxidant properties by DPPH radical scavenging activity assay, and antidiabetic properties by α-glucosidase inhibition assay, also LCMS/MS will be used to predict the compound from each extract. The result shows that 50% ethanol extract has highest phenolic and flavonoid content than others. It also has significantly higher antioxidant (p<0.05) and antidiabetic (p<0.05) properties than others. Meanwhile, LCMS/MS result of 50% ethanol extract predicts 6 chemical component, that quercetin is the most dominant compound. 50% ethanol extract of kenikir's leaves is superior from other extracts on phenolic and flavonoid content, antioxidant properties, and antidiabetic properties.