Introduction: Hypertension is the main risk factor for cardiovascular disease. There are many developed antihypertension drugs, one of them is focusing in ACE (Angiotensin Converting Enzyme) inhibition activity. ACE inhibition activity known can decrease vasoconstriction effect and also can decrease bradykinin degradation (vasodilator) by creating NO (nitric oxide). Methods: In this study, we conducted an in vitro ACE inhibition activity test which was obtained from watercress on 70% ethanolic extract and each fraction (n-hexane, ethyl acetate, and n-butanol). Results: Results of the study showed that ethanolic extract of watercress had ACE activity with IC50 value was 19.05 μg/mL and the highest IC50 of each fraction is ethyl acetate with IC50 value was 2,303 μg/ mL. n-butanol fraction had the highest total phenolic content with 15.798 mg GAE/g of the extract, while the highest total flavonoid content was obtained on ethyl acetate fraction with 82.847 mg QE/g of the extract. Conclusion: The results suggest that Watercress (Nasturtium officinale R. Br.) possess ACE inhibitory activity. © 2017 Phcog.Net.