Résumé : Purpose High intake of sugary soft drinks (SSDs or sodas) contributes to detrimental cardio-metabolic indicators in youth. Monitoring SSD consumption is informative for risk assessment but lacking in Eastern Europe. This study aims at describing time trends in the national prevalence of daily consumption of SSDs and related socioeconomic differences among Eastern European adolescents between 2002 and 2018.Methods We used 2002, 2006, 2010, 2014 and 2018 data of the ‘Health Behaviour in School-aged Children’ school-based study. Nationally-representative samples of adolescents aged 11, 13 and 15 years were included (n=325,184 from 14 countries; 51.2% girls). Adolescents completed a standardized questionnaire in class, including a short, validated food frequency questionnaire. We categorised adolescents into three socioeconomic groups based on the relative family affluence scale (FAS). Adjusted prevalence of daily SSD consumption by survey year and time trends between 2002 and 2018 were computed at the country level using multilevel logistic models (overall and by FAS groups). ResultsIn 2018, the prevalence of adolescents consuming SSDs everyday varied considerably between countries [range, 5.1%-28.1%], with prevalence higher than 20% in 5/14 countries. Between 2002 and 2018, the prevalence of daily SSD consumption declined in 10/14 countries (P for linear trends ≤0.004). The largest reductions were observed in Slovenia (OR 0.48, 95%CI: 0.45-0.50) and the Russian Federation (OR 0.67, 95%CI: 0.64-0.70). Daily SSD consumption reduced at faster rates among the most affluent adolescents (who were larger consumers in 2002 however) than in the least affluent adolescents in 11/14 countries (P for linear trends ≤0.004). Thus, differences between FAS groups narrowed over time, or even reversed, leading to larger proportions of daily consumers in the least affluent adolescents in 2018 in 5/14 countries (P≤0.05). Social patterning was similar among boys and girls, and in all three age categories. Conclusions Daily adolescent consumption of SSDs decreased between 2002 and 2018 in most Eastern European countries, mainly driven by larger declines among higher affluence adolescents. These results are useful to evaluate and plan interventions promoting healthy childhood dietsin the context of the nutrition transition.