In this study, it was aimed to investigate the antibacterial activities of the cationic porphyrin derivatives against some multi drug resistant clinical bacterial isolates and standard strains for the development of potential antibacterial agents. In addition to the standard strains, methicillin-resistant Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa clinical isolates were studied. We synthesized eight (P1-P8) cationic porphyrin derivatives. The minimum inhibitory concentrations (MIC) of these substances were determined by micro dilution method. Ciprofloxacin was used for quality control. The study was repeated three times. All porphyrin derivatives exhibited antibacterial activity at different levels according to the studied bacteria. The strongest antibacterial activity was obtained with compounds P6, P7 and P8. These compounds were found to have MIC values of <5-156 mu g/ml. Because of the low MIC values, it has been concluded that these synthesized porphyrin derivatives may be high-potency agents against bacteria with high resistance profile.