Introduction: The risk factors of cardiovascular disease (CVD) can be tracked from childhood into adult life. Diet quality exerts a great influence on incidence of these risk factors. The aim of the present study, conducted within the framework of the Tehran Lipid and Glucose Study, was to assess the trend of diet quality in relation to the recommendations for prevention of cardiovascular disease during a 6.7 year follow up among children and adolescents. Materials and Methods: Longitudinal study dietary data for 113 children and adolescents was collected using two 24-hour dietary recalls and a food frequency questionaire during the three study phases of study. Diet quality was compared with dietary recommendations for prevention of cardiovascular disease in children and adolescents( poor, moderate, good diet quality). Trends in diet quality score, were assessed during a 6.7 y of follow up. Results: Mean±SD age of participants was 11.45±4.2. The distribution of subjects in the category of “poor diet quality”increased from 8.8% at the start of the study period to 28.3% and 32.4% in the second and third phases respectively. At the beginning of the study, over 80% of subjects had “moderate quality diet” which decreased to 70% and 65% in the 2nd and 3rd phases respectively. More than 10% of subjects had “good diet quality” which decreased to less than 3%  in the 2nd and 3rd  phases of the study. A significant decrease was also observed in diet quality of participants in phases 2 and 3 compared to the beginning of the study (p<0.05). Conclusion: Results showed that trend of diet quality of children and adolescent compared to reccomendations for prevention of CVD seem unfavorable.