Abstract : Pseudomonas aeruginosa is an ubiquitous bacteria, has ability to adapt to different environments and causing in humans specially in Immunocompromised persons and hospitals. So the study aimed to detect the correlation between gene expressions of oprD and each of mexA and mexB genes in Pseudomonas aeruginosa isolates, fifty P. aeruginosa isolates were isolated from different clinical samples, detection of efflux pumps activity in P. aeruginosa phenotypically was done by Cather wheel method. Study genes expression of efflux pump genes under ciprofloxacin antibiotic stress and Et.Br. Results of oprD Ct values ranged from 20.56 to 24.98 with an average of 23.141. mexA Ct values were ranged from 32.1 to 36.79 with average 34.337 and results of mexB Ct values were ranged from 14.74 to 19.96 with average 16.791 compare to rpsL (Ct = 11.14) reference gene. The results showed that mean of Ct of gene expression was noticed when put them under stress of Et.Br. + CIP and CIP in mexA was 37.195 and 34.702, respectively, compare to control 34.337, on the other hand the gene expression between both treatments was over expressed in treatment of CIP 32 compare to CIP+Et.Br. The results of Cather wheel method expression was noticed when put them under stress Et.Br. + CIP and CIP in mexB gene expression was 19.626 and 18.872, respectively compare to control 16.791, In conclusion the both treatments compare to control not induce the expression of mexB genes, on the other hand the gene expression between both treatments was expressed in treatment of CIP 32 compare to CIP+Et.Br.