Hypertension in Indonesia is an important health problem, due to the high of prevalence and long-term impact. Bitter melon (Momordica charantia L.) leaves has been widely used as a traditional medicine to treat hypertension, but has not been studied as Angiotensin Converting Enzyme inhibitor. This leaves contain phenolic and flavonoids compounds. The aims of study was to investigate potency of 80% ethanol extract from bitter melon leaves as antihypertensive using ACE-kit WST (Dojindo, Japan) and determining total of phenolic expressed in gallic acid equivalents (GAE) and total flavonoids in quercetin equivalent (QE). The test results showed IC50 values from ethanol extract by inhibition of ACE activity was 7.52 µg/mL. Determination of total phenolic and total flavonoid from the extract were 20.717 mg /g GAE and 4.772 mg /g QE.