Abstract: The antioxidant activity of two methanolic fractions (C1, C2) of R. communis was determined by three methods: Lipid peroxidation by ferric thiocyanate method and free radical scavenging effect on 2, 2-diphenyl-1-picrylhydrazyl radical (DPPH) and hydroxyl radical generated from hydrogen peroxide. C1 and C2 at various concentration possessed significant antioxidant activity (p<0.05) when compared with antioxidant standards Butylated Hydroxy Anisole (BHA), ascorbic acid and α-tocopherol used in the assay. C1 had percentage inhibition of 93.98% while C2 gave 90.10% inhibition at 0.8 mg mL-1 in the lipid peroxidation/ferric thiocyanate test. In the DPPH assay, C1 had inhibition of 73.71% while C2 gave 87.92% at 1.0 mg mL-1. While in the hydroxyl radical scavenging assay, the inhibition of C1 was 85.07% while that of C2 was 94.91% at 0.1 mg mL-1, both extracts therefore, showed comparative antioxidant activities at the concentrations used. C1 golden brown coloured oil was analysed using gas chromatography/gas chromatography-mass spectrometry. Four components were obtained, Methyl ricinoleate (46.68%), Ricinoleic acid (34.41%), (Z, Z)-9, 12-Octadecadienoic acid (12.99%) and (Z, Z)-9, 12-Octadecadienoic acid, methyl ester (5.92%). These chemical constituents were assumingly responsible for the observed antioxidant activities of methanolic extracts from R. communis seeds.