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: Klebsiella pneumonia is a major nosocomial pathogen causing pneumonia, urinary tract infections, and bacteremia, particularly in immune-compromised patients. The aim of our study was expression of OMPK36 and OMPK35 in ESBLs production and non-ESBLs K.pneumoniae. Materials & Methods: Clinical isolates of K.pneumoniae were identified. ESBLs were assayed by Phenotypic (screening and confirming) and genotypic (PCR) methods. OMPK35 and OMPK36 were tested by polymerase chain reaction and SDS- PAGE. Findings: Our findings showed that 42.3% of K.pneumoniae were ESBLs positive. Twenty-two K.pneumoniae producing ESBLS and Twenty-two non-ESBLs K.pneumoniae were selected for porines detection. We found out that 54.54% and 72.72% of K.pneumoniae producing ESBLS were positive for Ompk35 and Ompk36 respectively, while our findings in non-ESBLs K.pneumoniae showed that 95.94% and 100% of isolates were positive for Ompk35 and Ompk36, respectively. Discussion & Conclusion: Many of clinical isolates of non- ESBL K. pneumoniae had expressed both Ompk35 and Ompk36 porins, while our results in ESBLs positive K.pneumoniae had only showed expression of Ompk36. A few of non-ESBLs and ESBLs K.pneumoniae were found as negative for both OMPK35 and OMPK36. Our findings released that lack of porins in K.pneumoniae are defined as an antibiotic- resistant mechanism in many isolates.