We aimed to determine single strand conformation polymorphism (SSCP) of selected waa cluster genes (waaA, waaE, waaL, waaQ and waaZ) involved in core lipopolysaccharide (LPS) synthesis in reference and epidemic strains of Klebsiella pneumoniae. Number of 24 reference strains belonging to serogroups O1, O2a, O2a2e, O2a2e2h, O2a2f2g, O3, O4, O5, O7, O8, and O12 was tested together with 13 epidemic strains from 5 outbreaks and 6 casual isolates using PCR and Multitemperature-SSCP. Based on PCR-SSCP results, from 4 to 8 patterns (genotypes) were distinguished for each analysed gene. Predomination of single genotype ranging from 28% to 76% for waaL and waaE respectivelly was observed in tested strains. The average predomination for other genes was about 36%. Although no correlation was observed between genotypes and serogroup of tested strains, it is notheworthy that epidemiologically linked isolates belonged to the same genotype. Therefore reported here heterogeneity of tested genes may be potentially useful for K. pneumoniae strains subtyping by SSCP or DNA sequencing.