Galing (Cayratia trifolia Domin.) have been used empirically to treat various diseases, one of them is antidiabetic. Objective: To determine the phytochemical content and the activity of the ethanol extract of the galing stem as antioxidant and antidiabetic. Method: The galing stem extract was investigated for phytochemical by Thin Layer Chromatography (TLC) and its antioxidant activity using DPPH scavenging activity assay. In vivo, antidiabetic test was conducted by animal diabetes modeling that has given streptozotocin 150 g/kg BW and 10% of sucrose solution intraperitoneally. The average level of fasting blood glucose at 307 mg/dL. Mice were divided into 6 groups, normal control group, diabetes induction group, positive group (treated by glibenclamide) and treatment group consisted of three groups were treated by ethanol extract of galing stem in dose 400, 500, and 600 mg/kg BW, respectively. Mice treated with appropriate doses of each treatment once a day for 7 days. The measuring blood glucose level was using a photometer 5010V5+. Results: The ethanol extract of galing stem contained the alkaloid, flavonoid, saponin, tannin, and triterpene. It is potential as an antioxidant with the IC50 61,52 mg/L which indicated that the extract had strong antioxidant. The antidiabetic activity showed that the effect of extract 400 and 500 mg/kg BW are not different significantly with glibenclamide in reducing blood glucose levels subset of the statistics ANOVA (p> 0.05). Conclusion: The ethanol extract of galing steam is potent as an antioxidant due to the phytochemical content inside particularly the flavonoid compound.