Results: 1361 school children aged 12 and 1286 aged 15 in all 22 Districts of the city were examined by two well-calibrated examiners Age group Fluoridated areas Non - Fluoridated areas p-value% DMF-T±SD% DMF-T±SD 12 38.2 0.85±1.37 67.0 2.16±2.39 0.000 15 55.0 1.60±2.05 79.5 3.19±2.92 0.000 Age group DMF-T Fluoridated areas Non - Fluoridated areas OR 95% CI 12 > 312.7% 34.9% 3.70 2.78 - 4.93 >52.5% 13.7% 6.2 3.77 - 10.21 15 >59.5% 27.0% 3.51 2.53 - 4.86 Conclusion: this study showed that water fluoridation had improved significantly the dental caries status of the children in fluoridated areas in HoChiMinh City as compared to non-fluoridated ones.