A wide variety of organisms are emerging as resistant to antibiotics, and multiple drug resistant organisms pose a serious threat to the treatment of infectious diseases. Hence, mushroom derived antimicrobial substances have received considerable attention in recent years. In this study antagonistic effects of the methanol, acetone and water extracts of mycelia and fruiting body of Ganoderma lucidum were tested against seven bacterial species: Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Enterobacter aerogenes, Klebsiella pneumoniae, and Salmonella typhimurium. All the extracts exhibited various degree of inhibition against all test bacteria. Widest inhibitory zone (33mm) was obtained with mycelial acetone extract of Ganoderma lucidum against Pseudomonas aeruginosa. Lowest zone of inhibition (7mm) was observed with fruiting body aqueous extract against Staphylococcus aureus and Klebsiella pneumoniae. Minimum inhibitory concentration (MIC) of acetone extract of fruiting body and mycelial extract was determined, for mycelial extract it ranged between 4 to 12mg/ml and for fruiting body extract it ranged between 15 to 35 mg/ml for test bacteria.