Introduction: Hypertension is a leading problem in Indonesia, because of the high prevalence and the long term effect. Bitter melon leaves (Momordica charantia L.) has been traditionally utilized to treat hypertension, yet not many studies explained the antihypertension effect of this plant. Methods: This study was conducted to test the benefit of bitter melon leaves as antihypertension using angiotensin converting enzyme inhibition activity in 80% ethanolic extract and its fractions (n-hexane, ethyl acetate, and n-butanol) using ACE kit-WST (Dojindo, Japan). Then the antihypertension activity was associated with the phenolic content which was expressed in gallic acid equivalent (GAE) and total flavonoid in quercetin equivalent (QE). Results: Result of the study showed that the IC50 value obtained from the ethanolic extract to inhibit ACE activity was 7.52 μg/mL and the highest inhibition obtained in ethyl acetate fraction with IC50 value was 4,29 μg/mL. Phenolic total and flavonoid total determination also showed that the highest content obtained in ethyl acetate fraction with 18.752 mg GAE/gr extract and 8.310 mg QE/gr extract, respectively. Conclusion: According to the study, it could be concluded that bitter melon (Momordica charantia L.) leaves provide inhibition activity against Angiotensin Converting Enzyme (ACE) and chemical compounds that were expected to play an active role in inhibiting ACE were flavonoid and tannin.