Abstarct: The infectious diseases cause premature death. To control such human infectious diseases, various commercial antibiotics have been applied around the world. On the other hand, long-term use of these antibiotics have led to the emergence of multidrug-resistant bacteria and subsequently significant clinical problems. The aim of this study was to investigate the antibacterial effect of ganoderic acid extracted from two verities of Ganoderma lucidum, red and yellow, on 5 different gram-positive and gram-Negative bacteria, included: Pseudomonas aeruginosa (ATCC27853), Esherichia coli (ATCC25922), Staphylococus aureus (ATCC25923), Bacillus subtilis (PTCC1715), Micrococcus luteus (ATCC9341) (1715 (PY79), .The results indicated that the amount of ganodric acid in dry weight of the fungus in red varity with less bitter taste was 2.140 mg/g and in fungi with more bitter taste and yellow color was 3.264 mg/g. According to the extracted ganoderic amount of both fungi, solutions with different concentrations of ganodric acid were prepared from both red and yellow fungi, following that the standard microdilution method was used to determine the minimum inhibitory concentration (MIC) and the minimum lethal concentration (MBC). The range MIC/MBC in µg/ml for Staphylococcus aureus and Escherichia coli used in this study were 26.5/26 µg/ml and 23/29 µg/ml for red and yellow fungus respectively. to Micrococcus luteus, Pseudomonas aeruginosa, Bacillus subtilis this amount were 34/45 µg/ml and 34/46 µg/ml for red and yellow varieties respectively which showed that the antibacterial property was dependent on the amount of ganoderic acid and increasing the ganoderma acid of Ganoderma lucidum would increase its antibacterial properties.