There is a growing body of evidence on the association of periodontal pathogens present in periodontal environment and periodontal pathologies in adults while the so far existing data on periodontal microbiology of infants and children have been limited. Aim: The aim of this study was to identify the known periodontal pathogens in infants with ECC and children cared of by the Teaching Hospital in the city of Brno. Methods: Altogether 37 infants aged 2-4 years and 96 children (mean age 14.57, SE=0.84) were involved in screening periodontal pathogens in both bleeding and healthy gingival sites. Material from gingival sites was absorbed to endodontic paper points and processed in ParoCheck® kits (Greiner Bio-one GmBH, D). Bacterial species were identified by means of hybridization in situ method using 16S rRNA fragment and highly conserved primer labelled by fluorophore (Cy5). Hybridized samples were labelled by strain specific DNA-sondes and identified according to ParoCheck®Report-Software. Findings in gingival bleeding and healthy sites were compared (chí² test; P = 0.05). Results: Infants - frequency in bleeding gingival sites (%): A. actinomycetemcomitans (AA) 32.4, P. intermedia (PI) 5.4, F. nucleatum (FN) 54.1, T. denticola (TD) 10.8, T. forsythensis (TF) 2.7, P. nigrescens (PN) 5.4, all significantly more often than in healthy sites (P Schlagwörter: gingivitis, pedodontics, ELSPAC, ECC, periodontal pathogens