Ganoderma lucidum (Leyss.:Fr.) Karst is one of the medicinal mushrooms, which possesses enviable antioxidant properties. Objective of this investigation was to evaluate antioxidant activity, reducing power, scavenging abilities on 1.1-diphenyl-2-picrylhydrazyl (DPPH) radicals and chelating effects on ferrous ions of hot water extracts obtained from carpophore and spores of this mushroom. Hot water extract from carpophore (Gl-I) showed high antioxidant activity of 85.7 ± 0.7%, at 10 mg/ml, while antioxidant activity of hot water extract from spores (Gl-Is) was 9.2 ± 0.3% at 10 mg/ml. Reducing power of Gl-I reached a plateau of 3.4 ± 0.1 at 20 mg/ml, and 0.3 ± 0.0 at 20 mg/ml for Gl-Is. At 10 mg/ml, scavenging ability on DPPH radicals of Gl-I increased to 96.8 ± 2.5%, whereas Gl-Is scavenged DPPH radicals by 69.6 ± 2.5% at 10 mg/ml. Gl-I chelated 81.6 ± 3.6 % of ferrous ions at 20 mg/ml, while the chelating effect of Gl-Is was 73.8 ± 1.7%. The antioxidative activities of hot water extracts from carpophore and spores of the mushroom G. lucidum were concentration dependent and increased with an increase in the concentration.