Regarding to the importance of food habits and the probable role of obesity in dental caries, this study was done to assess the relationship between teeth decay index in children and body mass index, and food habits in dentistry clinic of Tabriz university of medical sciences. Materials and Methods: In this cross-sectional analytic study 202 children aged 3-12 years old were selected randomly. For assessing dental caries, decayed, missed, and filled teeth index and for evaluating food habits, semi quantitative food frequency questionnaire were used. Data were analyzed using Correlation test and Regression analysis. Results: The overall mean of decayed, missed, and filled teeth index in the children of this study was 7.61±3.80. There were significant reverse correlations between this index and age (r = -0.176), and fruit consumption (r = -0.155) (P<0.05). There was no significant correlation between dental caries and body mass index (P>0.05). Considering the last regression model, age, mother job, and frequency of nuts consumption were significant predictors for decayed teeth number. Conclusion: The results of this study indicated that high fruit consumption was associated with less dental caries and among foods which were evaluated, consumption of nuts was significant predictor for decayed teeth number.