Klebsilla pneumoniae is one of must opportunistic pathogens that causes nosocomial infection, UTI, respiratory tract infections and blood infections. ZrO2 nanoparticles have antimicrobial activity against some pathogenic bacteria and fungi. Ceftazidime is one of third generation cephalosporins groups of antibiotecs, characterized by its broad spectrum on bacteria in general and particularly on Enterobacteriaceae family like Klebsiella spp. Method: Diverse clinical samples of Klebsilla pneumoniae were isolated from several hospitals in Baghdad – Iraq and ZrO2 nanoparticles was investigated against it. Ceftazidime was also investigated against K. pneumoniae. Both of ZrO2 nanoparticles and ceftazidime were mixed together and investigated against K. pneumoniae. Results: The result showed that ZrO2 nanoparticles were effectivity on inhibiting opportunistic pathogens. By using zirconium oxide nanoparticles on Klebsiella pneumonia isolates in 24h. of incubation time, inhibition zones were (38,34,10,10,8,0) mm respectively on agar plates. By using ceftazidime alone against the same bacteria inhibition zones were (40,32,10,9,8,0) mm. respectively. Conclusion:The present study results that the antibacterial activity of ceftazidime against bacteria was increased when combination between ZrO2 nanoparticles and the antibiotic had done, because, inhibition zones in case of mixing both of ZrO2 nanoparticles and ceftazidime were (43,40,12,12,10,0) mm respectively. So that we can conclude that the combination of zirconium oxide nanoparticles (ZrO2) and ceftazidime was a useful method for the treatment of Klebsilla pneumonia that cause nosocomial infection, UTI, respiratory tract infections and blood infections.