This cross-sectional study was conducted to apply ICDAS on evaluating dental caries among 12 year-old children in the An Lac Secondary school. The study included 284 school children aged 12 years old. Dental caries status was evaluated by ICDAS II following 3 criteria: detection of lesion, assessment of severity and assessment of activity. Chi-square and Independent samples t test were applied. The results show that: 95.1 percent children had caries lesions (including noncavitated and cavitated lesions), D1MF - T = 6.36
D1MF - S = 8.16
79 percent children had dentine caries lesion D3MF-T= 2.54
D3MF - S = 84. There were significant differences in mean of D1MFT, D1MF-S, D3MF-T and D3MF-S between males and females (p 0.05). There was also a strong relation in D1MF-S and D3MF-S (r