摘要:Background: Nowadays, due to increased public awareness about water pollution and water borne diseases as well as water network deficiencies, bottled water consumers have increased dramatically worldwide, including Iran. Pseudomonas aeruginosa is an opportunistic human pathogen capable of causing widespread infections in burn and immune-compromised patients. The aim of this study was to investigate, P. aeruginosa in bottled waters selling in Iranian markets.Methods: One hundred and twenty samples of five unknown (not famous) domestic bottled water brands were purchased from Tehran retailers during 2013. The samples were evaluated for the presence of P. aeruginosa. In addition, heterotrophic plate counts were determined by incubation at 37 °C for 24 h.Results: P. aeruginosa was detected in 36.7% (44 samples) of all samples examined. In addition, heterotrophic bacteria in 32.5% (39 samples) of the samples were higher than 100 CFU/mL, while in 7.5% (9 samples) of the samples HPC relied between 20 and 100 CFU/ml.Conclusion: In contrast to public believe, bottled waters are not free of microorganisms, and it is suggested that authorities should provide stricter monitoring and control plan for water resources and plants. Concerning HPC and P. aeruginosa brands B and D were not suitable for drinking. Keywords: Heterotrophic plate count, Pseudomonas aeruginosa, Bottled water