Objectives: the aim of this study was to compare saliva factor in 2 groups of 9 - 10 years-old school children with low and high prevalence of caries in Binh Chanh. Materials and method: a convenient population of 338 children aged 9 - 10 was selected from Nguyen Van Tran primary school to evaluate dental caries, among which 153 children were divided into 2 groups (low caries: 62 children with DMF-T=0 or dmf-t≤1, high caries: 91 children with DMF-T and dmf-t≥SiC).