Thirty three isolates of K. pneumoniae were studied. The strains were cultured from different clinical specimens received from patients hospitalised at a Neurosurgery Unit at the Dr Jurasz University Hospital in Bydgoszcz. Production of ESBL was assessed using double disk synergy test. The genomic DNA was extracted from the strains separated by PFGE after digesting with XbaI endonuclease. Production of ESBL was detected in 81.8% of K. pneumoniae isolates. Molecular typing results revealed a great genetic diversity among K. pneumoniae isolates. All repeated PFGE patterns were detected in 12 (36.3%) K. pneumoniae isolates.