Klebsiella pneumoniae is one of the most important hospital pathogens, particularly concerning the multidrug-resistant strain ESBL+. The aim of this study was to evaluate nosocomial infections with K. pneumoniae ESBL+ in the context of infection location, risk factors, and prognosis. This hospital study was conducted retrospectively and covered a 3 months' period. The infection with K. pneumoniae ESBL+ was diagnosed in 36 patients (19 women and 17 men) of the mean age of 74.2 ± 14.8 years. The number of infected patients amounted to 2.2% of all patients admitted to Czerniakowski Hospital in Warsaw, Poland, over the study time. Twenty of these patients died (13 women and 7 men), representing 14% of all hospital deaths at the time. The infection with K. pneumoniae ESBL+ occurred most frequently in the department of internal diseases, and rarely in neurology or intensive care wards. Bacteria was most often isolated from the urine, with the most distinct association between the use of urinary catheters and death (p = 0.019). We conclude that infections with K. pneumoniae ESBL+ were associated with over 55% mortality and usually occurred in the setting of internal diseases. Deaths due to K. pneumoniae ESBL+ infection were significantly related to the use of urinary bladder catheters.