Coordenaç~ao de Aperfeiçoamento de Pessoal de Nível Superior (CAPES/ Proc. 1732109). Erika V.M. Orozco was supported by a fellowship provided by the Conselho Nacional de Desenvolvimento Científico e Tecnol ogico (CNPq/140824/2015-4). Andr e L.M. Porto was supported by a grant 2014/18257-0 and grant 2016/20155-7, S~ao Paulo Research Foundation (FAPESP) and Conselho Nacional de Desenvolvimento Científico e Tecnol ogico (CNPq/Proc. 302528/2017-2). This work was supported by the Coordenaç~ao de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001. The author also acknowledge the Chromatography Group (Instituto de Química de S~ao Carlos - USP), including Dr. Guilherme M. Titato for the QqToF analysis (grant 2004/09498-2, S~ao Paulo Research Foundation).In this study, we report our contribution to the application of the copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction for the synthesis of β-keto-1,2,3-triazole derivatives 3a-f from ethinylestradiol and their application in the inhibition of two human cancer cells lines: human breast adenocarcinoma (MCF-7) and human hepatocellular carcinoma (HepG2). The β-keto-1,2,3-triazole derivates 3a-f exhibited moderate cytotoxic activity for the HepG2 cells with IC50 values of 29.7 μM (3a), 16.4 μM (3b), 17.8 μM (3c), 20.4 μM (3d), 28.1 μM (3e) and 28.2 μM (3f). The semi-synthetic β-keto-1,2,3-triazoles derivatives 3a-f were all characterized by FT-IR, NMR, HRMS and [α]D.