Klebsiella pneumoniae is a notoriously known opportunistic pathogen that causes a broad range of healthcare-associated infections, especially the urinary tract infections. The immediate increase in the antimicrobial resistance, particularly the resistance to the β-lactam antibiotics, has become a significant clinical and social health issue on the global stage. The study was intended to phenotypically and molecularly characterize β-lactam-resistant K. pneumoniae isolates that were collected on patients diagnosed with urinary tract infections. Two hundred and fifty urine samples were cultured, and a total of 35 Klebsiella pneumoniae isolates were detected, representing 16.06% of the positive cultures. The isolates showed high resistance rates as all the isolates were fully resistant to amoxicillin-clavulanate, ticarcillin-clavulanate, ceftazidime, cefotaxime, ceftazidime-avibactam, and fosfomycin. Carbapenems resistance rates were also high with 83 percent of the isolates resistant to imipenem and meropenem. PCR analysis revealed that all carbapenem-resistant isolates (n = 29) carried the metallo-β-lactamase genes blaNDM and blaFIM, and the presence of the genes was strongly related to carbapenem resistance (p < 0.01). The great popularity of metallo-β-lactamase-producing K. pneumoniae with multiple β-lactam resistance highlights the necessity to improve the means of infection control and to develop effective alternative therapeutic strategies to reduce the number and effects of such multidrug-resistant pathogens.