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Klebsiella pneumoniae is a gram-negative bacillus of the Enterobacteriaceae family. Despite being part of the natural human microflora, this is an opportunistic pathogen and a major cause of nosocomial infections. The increased emergence of multidrug resistance in Klebsiella pneumoniae has limited the treatment options for this bacterium. Carbon nanotubes (CNT), by improving the stability and solubulity of drugs, could increase the effectiveness of drugs for treatment. The aim of this study is to investigate the antibacterial effect of nanofluid containing functionalized multi-walled carbon nanotubes (f-CNT-NF) on Klebsiella pneumoniae isolated from clinical specimens. For the strain confirmation, biochemical ,API20E kit, and additional differential tests were performed, and antibiotic susceptibility test was performed by the disk diffusion method. The studied strain showed a resistance to all antibiotics such as cefepime.The minimum inhibitory concentration (MIC) was determined using the antibiotic micro dilution method. The MIC was determined in five effect modes including antibiotic (Ab), nanofluid containing functionalized multi-walled carbon nanotubes (f-CNT-NF) , nanofluid containing multi-walled carbon nanotubes (CNT-NF) ,Ab in combination with f-CNT-NF and Ab with CNT-NF. Nevertheless the individual effects of 10 µg mL^-1 cefepime or 80 µg of nanofluid with f-CNT-NF did not inhibit the growth of the bacteria, but the co-administration of 10 µg mL^-1 cefepime with 80 µg of the f-CNT-NF could inhibit the bacteria`s growth. It was concluded that f-CNT-NF could be more effective in drug delivery at lower concentrations than the free state, which could be used as a tool for optimal drug delivery.