Phenol and phenolics are widely used industrial chemicals and they are hazardous environmental pollutants when they are released from wide range of industrial processes. This study was carried out to investigate the antibacterial potentials of three structural isomers of the aminophenol. Antibacterial activities of o-aminophenol, m-aminophenol and p-aminophenol were initially determined using the standard disc diffusion method. The results obtained from these studies demonstrated that p-aminophenol could inhibit the bacterial growth much better than the other two structural isomers when they were used in the same concentrations. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of p-aminophenol were then determined against gram (+) and gram (-) reference strains using the broth macrodilution method. MIC and MBC values were found between 31,25 and 500 mu g/mL. pH of the growth medium had a slight effect on the MIC values and the MIC value was higher in the growth medium with a lower pH. Time-kill analyses of p-aminophenol were performed against Staphylococcus aureus and concentration dependent killing curves were obtained. Postantibiotic effect of p-aminophenol was also investigated against Staphylococcus aureus which was the most susceptible strain and found to be approximately 15 min for the MIC concentration. From our experimental results, we conclude that p-aminophenol, but not the other two structural isomers, displays a potent antibacterial activity against standard reference strains. We here also present some novel data on the antibacterial activity of p-aminophenol.