Klebsiella pneumoniae are Gram-negative which cause many diseases such as urinary tract infections, respiratory tract infections and septicemia. Inulinase is an enzyme used in food manufacture and pharmaceuticals. Inulinase is used in decreasing lipid ratio and, cholesterol in blood and considered as a prebiotic factor inside intestine. Many microorganisms can produce inulinase, such as yeast, fungi and bacteria; among such bacteria: Bacillus spp., Arthrobacter spp., and Pseudomonas spp. but there are no studies about inulinase production by K. pneumoniae have been reported. So the current study aims at investing the ability of producing and purification inulinase by K. pneumoniae. Method: K. pneumoniae were isolated from many hospitals and screened for the production of inulinase. Isolation percentage was 32%. A combination between the enzyme and the ceftazidime were assayed for detecting the antibacterial activity agonist Gram positive and Gram negative bacteria were done. Results: It is found that K. pneumoniae K4 isolate is the best producer of this enzyme. Inulinase, purified with ammonium sulfate at 70% saturation with specific activity 7.01 U/mg protein. As well, it's found that inulinase had increased the activity of ceftazidime against bacteria when combination between this enzyme and the antibiotic had done. Conclusion: This study proves for the first time that K. pneumoniae can produce inulinase which can be used in tremendous applications and also proves the broad spectrum bioactivity of inulinase against microbial pathogens. Ceftazidime antimicrobial activity against bacteria, is increased when a combination between inulinase and ceftazidime had done.