This study was aimed to investigate the correlation between the protein composition of human mixed saliva from participants of a caries risk assessment study. The participating schoolchildren exhibited a caries incidence from 0.34 to 0.71 while ageing from 8 to 10 years. Three unstimulated mixed saliva samples of 111 subjects were collected during 2 years and 50 µl were analysed by reversed phase HPLC (RPLC) (Hewlett-Packard ChemStation LC 1100, Zorbax 300 SB-C8 column (4.6 x 150 mm, 3.5 micron) at 35 °C, UV detection at 215 nm). The protein content of nine fractions was determined using bovine serum albumin (BSA) as an internal standard. A cluster analysis (Ward method) with the protein contents of the nine protein fractions was performed, which allowed a separation of the subjects into two distinct cluster groups, distinguished to the two- or three-fold of the protein content for one group (Tab. 2). The number of test persons assigned to cluster 2 decreased dramatically with increasing age of children. Keywords: saliva, protein, caries risk, hplc, cluster analysis