OBJECTIVE The purpose is to investigate incidence of caries and unilateral mastication in adolescents, and to analyze the relationship between unilateral mastication and caries. METHODS By means of standard dental caries detection, unilateral mastication examination and questionnaire survey in students (160) among three junior middle schools in Chengdu, we analyzed the correlation between unilateral mastication and prevalence of dental caries. RESULTS According to the statistics,students with unilateral mastication had a 60.71% caries prevalence which was significantly higher than that of control group (40.68%). There was a significant positive correlation between unilateral mastication and dental caries prevalence (Phi = 0.198,P = 0.018). CONCLUSION Unilateral mastication and caries have a certain relevance, adolescents in Chengdu (14-15 year-old middle school students) with unilateral mastication have higher caries prevalence than that of none-unilateral-mastication. In the prevention of dental caries, the significance of preventing unilateral mastication should be highly valued.