Objective To carry out a phyto-chemical characterization of essential oil from Ocimum basilicum L. (O. basilicum) harvested in DR Congo and to assess the antioxidant potential of crude extracts with respect to the polarity for comparison reason. Methods The phyto-chemical characterization of essential oil produced by hydro-distillation was performed by coupled gas chromatography-mass spectrometer analysis and the antioxidant potential evaluation by in vitro 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity method. Results A previously weighed amount of fresh leaves of O. basilicum produced 0.65% of essential oil that led to the identification of a set of 84.44% out of 99.98% as major compounds (> 1.5%). The chemo-type of this essential oil was linalool-methyl chavicol. Chemical components of oil were characterized by oxygenated aromatic hydrocarbons (46.00%) and oxygenated monoterpenes (26.75%). With respect to the amount of components, methyl chavicol also known as estragole (35.72%) constituted the very large quantity afterward linalool (21.25%) and then epi-α-cadinol (8.02%), α-bergamotene (6.56%), eugenol (4.60%), 1,8-cineole (4.04%), germacrene D (2.06%), thymol (1.64%), and (E)-citral (1.55%), respectively. Essential oil exhibited antioxidant potential and IC