Introduction: Quorum sensing (QS) system is a complex cellular regulatory network activated in response to population size via auto inducer molecules (AI). luxS gene is an important recognized in QS some Gram-negative and Gram-positive bacteria which produce AI-2 molecules. Therefore, klebsiella isolated form urinary tract infections and the frequency of luxS gene in the isolates was studied.Materials & methods: A total of 80 clinical isolates of Klebsiella spp. were collected from urinary tract infection (UTI). The isolates were identified by biochemical tests. The specific luxS amplicon were identified by PCR.Findings: The results revealed 37 (46.2%), 16 (20.0%), 5 (6.2%), 6 (7.5%), and 16 (20%) of the isolates were K. pneumonia, K. oxytoca, K. rhinoscleromatis, K. ozaenaand K. mobile, respectively.  According to the PCR analysis, all the isolates present the luxS gene.Discussion & Conclusions: Our findings revealed luxS gene has high prevalence in Klebsiella spp. This system is associated with regulation of many physiological functions of bacteria such as biofilm formation therefore its expression level can be surveyed in correlation with the biofilm formation ability of the isolates in next study.