Aim: Evaluate the PRE-STARt intervention in five European countries (UK, Portugal, Spain, Germany and Greece). Methods: The 8 family based interactive workshops aimed to elicit positive lifestyle behavior change in 12-14 year olds. The written curriculum was underpinned by specific learning theories and philosophy. Demographic, biomedical, anthropometric and lifestyle behavior measures were collected at baseline, 3 and 6 months. Due to design differences across countries, the analysis assesses changes within each country. Results: 318 participants were recruited (50% male, 69% Caucasian ethnicity). Control group were more overweight than the intervention group (10%). Average time spent doing moderate-vigorous physical activity (MVPA) was 45 minutes/day. A trend towards increased MVPA at 6 months in the UK was observed (8 mins/day). The attendance data for change in MVPA at 6 months indicate a dose response. Those attending at least 4 workshops had significantly higher MVPA compared to those who attended less than 4 (OR:12.64 (3.63 to 21.66), 18.92 (5.74 to 32.09)). A trend towards clinical and statistical significant reduction in both BMI and weight for all countries was observed. The UK observed a non-significant reduction in self-reported sitting time on weekdays (1 hour/day). Eating behaviors improved in each country at 6 months; in Greece increased frequency of eating breakfast; a reduction in the number of days snacks eaten in the UK; a trend across all countries for increased fruit and vegetable consumption. Conclusion: The intervention is accepted by the target population. The data point to positive emerging trends in changes in health behaviors (both eating and activity) in addition to health outcomes namely a reduction in body weight and BMI. A definitive randomized controlled trial is required to test effectiveness and cost effectiveness of the intervention. Disclosure E.M. Brady: None. L.J. Gray: None. S. Weihrauch-Blüher: None. C. Edwardson: None. D. Harrington: None. R.T. Ribeiro: None. A. Vazeou: None. A.L. Northern: None. E. Alustiza: None. M. Davies: Advisory Panel; Self; AstraZeneca. Board Member; Self; AstraZeneca. Consultant; Self; AstraZeneca. Speaker's Bureau; Self; AstraZeneca. Advisory Panel; Self; Boehringer Ingelheim Pharmaceuticals, Inc.. Board Member; Self; Boehringer Ingelheim Pharmaceuticals, Inc.. Consultant; Self; Boehringer Ingelheim Pharmaceuticals, Inc.. Speaker's Bureau; Self; Boehringer Ingelheim Pharmaceuticals, Inc.. Advisory Panel; Self; Eli Lilly and Company. Board Member; Self; Eli Lilly and Company. Consultant; Self; Eli Lilly and Company. Speaker's Bureau; Self; Eli Lilly and Company. Advisory Panel; Self; Janssen Pharmaceuticals, Inc.. Board Member; Self; Janssen Pharmaceuticals, Inc.. Consultant; Self; Janssen Pharmaceuticals, Inc.. Speaker's Bureau; Self; Janssen Pharmaceuticals, Inc.. Advisory Panel; Self; Novo Nordisk Inc.. Board Member; Self; Novo Nordisk Inc.. Consultant; Self; Novo Nordisk Inc.. Research Support; Self; Novo Nordisk Inc.. Speaker's Bureau; Self; Novo Nordisk Inc.. Board Member; Self; Sanofi-Aventis. Consultant; Self; Sanofi-Aventis. Research Support; Self; Sanofi-Aventis. Advisory Panel; Self; Sanofi-Aventis. Speaker's Bureau; Self; Sanofi-Aventis. Advisory Panel; Self; Servier. Consultant; Self; Intarcia Therapeutics, Inc.. Speaker's Bureau; Self; Mitsubishi Tanabe Pharma Corporation.