Doxorubicin is a powerful anticancer antibiotic extensively used in the treatment of several types of cancers. Long-term administration of this drug results in cumulative dose related cardiotoxicity due to enhanced production of free radicals leading to oxidative stress. Our earlier investigations have demonstrated significant antioxidant, anti-inflammatory and antitumour properties of Ganoderma lucidum extracts. We extended our investigations to evaluate the protective effect of Ganoderma lucidum extract against doxorubicin-induced cardiotoxicity. Administration of 3 doses of doxorubicin, 6 mg/kg body weights, i.p. per each dose, alternative days, showed dear signs of cardiotoxicity in rats. The drug enhanced serum creatine kinase (CK) activity and lipid peroxidation in tissue drastically. The drug also induced significant decrease in GSH level and activities of CAT, SOD and GPx. Administration of methanolic extract of G.lucidum (500 and 1,000 mg/kg body weight) significantly increased the level of GSH and activities of CAT, SOD and GPx. Activity of CK was significantly lowered in a dose dependent manner. The treatment also caused significant decrease in lipid peroxidation (MDA). The results thus indicated that methanolic extract of G.lucidum prevented oxidative stress caused by doxorubicin administration and the increase in serum CK activity and lipid peroxidation in the tissue. The experimental findings suggest the therapeutic potential of G.lucidum as adjuvant in cancer chemotherapy.