Purpose: To evaluate the effect of sugar-free snacks on caries-related factors in 6- to 9-year-old schoolchildren. Materials and Methods: Two hundred seventy-one children at risk for caries as measured through the Cariogram were randomly assigned to three groups consuming twice-daily snacks containing Stevia, maltitol or sugar for 42 days. Parents filled out a standardised questionnaire regarding personal, medical and oral behavioural information. Bleeding on probing, plaque pH and salivary mutans streptococchi (MS) and lactobacilli (LB) were assessed at baseline (t0), 42 days of snack use (t1) and 120 days after the end of use (t2). The Cariogram calculation was repeated at t1. Treatment effects were estimated using linear mixed-effects regression models. Results: At t2, a decrease in cariogenic bacteria (MS X2 = 8.01, p 0.01 and LB X2 = 4.60, p = 0.03) and an increase of the minimum pH (F = 4.48, p 0.01), maximum pH (F = 2.88 p 0.01) and pH drop (F = 2.95 p 0.01) was recorded in the Stevia group compared to baseline. In the maltitol group, an improvement effect was noted: LB concentration decreased (p = 0.04) and maximum pH (F = 3.16 p 0.01) increased. Subjects classified by the Cariogram as have a low probability of developing caries increased in the Stevia and maltitol groups (X2(4) = 25.44, p 0.01, C*sV = 0.38 and X2(4) = 12.85, p = 0.01, C*sV = 0.27, respectively). Regression analysis underlines the effect of Stevia snacks on the cariogenic microflora, mainly on MS and plaque pH variations. Conclusion: The short-term administration of Stevia or maltitol snacks improves some important factors related to caries. This preventive strategy might be an additional means of combatting this common childhood disease. Keywords: caries, children, paediatric dentistry, snacks, stevia