Reactive dyes are resistant to natural biodegradation, due to the aromatic rings in their structure. Among dyes used in textile industry, Reactive Red- 120 (RR-120) is one of the frequently used dyes in textile industries and is a potential threat to the aquatic environment due to its poor biodegradability. The aim of this research is to analyze the antibacterial activity of Reactive Red-120 on E. coli and Bacillus subtilis with MIC, MBC and disc diffusion tests. In this study dilution test was used to finding the minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of the Reactive red-120. For disc diffusion assay test substance were testet at 125 μg, 250 μg, and 500 μg concentrations. MIC values of Reactive red-120 against Bacillus subtilis is 100 In this study dilution test was used to finding the minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of the Reactive red-120. For disc diffusion assay test substance were tested at 125, 250, and 500 μg concentrations. MIC values of Reactive red-120 against Bacillus subtilis is 100 μg/ml, and MBC values was 1200 μg/ml, MIC values of Reactive red-120 against E. coli is 50 μg/ml, and MBC values is 800 μg/ml. The result of this study showed that Reactive red- 120 has not antimicrobial activity against Bacillus subtilis and E. coli, because diameter of inhibition zone at all concentration was zero mm. So, it can be concluded that Reactive red-120 might not pose a potenti
