Robusta coffee shell (Coffea canephora) is a waste from coffee plantations that has the potential as an environmental pollutant. Coffee skin shell contains cellulose, hemicellulose, and lignin. The content through the pyrolysis process will be decomposed into phenolic compounds, carbonyls, acids, and so on in the form of liquid smoke. Phenol compounds in liquid smoke have the potential as antioxidants, which can inhibit or prevent the oxidation process. This study aims to determine the antioxidant activity of the liquid smoke of robusta coffee shell shells using the DPPH method (2,2-diphenyl-1-picrylhydrazyl). The liquid smoke used as an antioxidant is grade I liquid smoke. Based on the research results, the phenol in grade I liquid smoke has a concentration of 0.0179%. The antioxidant activity test of robusta coffee shell liquid smoke obtained an IC50 value of 0.0071%. This ability as an antioxidant is shown by liquid smoke in reducing free radicals from DPPH reagents. Based on the IC50 value , it is known that the liquid smoke of robusta coffee shell has the ability as a relatively strong antioxidant. Keywords: Liquid smoke, antioxidants, DPPH.