Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): This study was partly financed by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) – Finance Code 001, and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Brazil. Background Lifestyle changes are crucial to preventing diabetes and its cardiovascular complications, including maintaining a physically active lifestyle. Morever, patient education is essential to promote diabetes self-management and health condition control. However, programs that combine physical exercise and lifestyle education are still poorly implemented in low- and middle-income countries, such as Brazil. The Diabetes College Brazil Study is a pioneer randomized clinical trial (RCT) designed to promote behavioral changes in adults with diabetes and prediabetes. PURPOSE: To test the feasibility, acceptability, and preliminary effectiveness of Diabetes College Brazil Study interventions (Exercise (Ex) vs. Exercise and Lifestyle Education (ExLE)) as part of the preparation for the development of the RCT. Methods This pilot randomized trial (NCT03914924) had two parallel arms: ExLE program (12 weeks of exercise and educational interventions) and Ex program (12 weeks of exercise intervention only) (Figure 1). Feasibility (eligibility, recruitment, retention, completeness of RCT variables measures and participation rates), acceptability (satisfaction with interventions), and preliminary effectiveness of interventions (comparison of RCT variables measured in pre-and post-assessments) were evaluated. The preliminary effectiveness of the interventions was analyzed from the values of the difference between post-and pre-intervention measures (Δ post-pre) using both per-protocol (PP) and intention to treat (ITT) analysis for the comparison between groups (Ex vs. ExLE). The value 0 was imputed to replace the missing data in the analysis that followed the ITT principle. The results were reported as estimates of effect (95% confidence interval (CI) of the difference) for variables with normal distribution. RESULTS: Thirty-seven individuals participated in the study (ExLE: n = 18, 56.9±9.5 years old, 55.6% female, 5.6% prediabetes; Ex: n = 19, 59.5±7.3 years old, 52.6% female, 21.1% prediabetes). Eligibility, recruitment and retention rates were 16%, 100% and 82% respectively. The completeness of RCT variables measures was higher in the pre-intervention assessment. Missing data in the post-intervention assessment were mainly related to modifications in research procedures due to the COVID-19 pandemic. Participation rates in supervised exercise sessions and education classes were 76% and 71%, respectively (total sample). Interventions were highly acceptable to participants. There was a trend towards better results in the ExLE than Ex for most variables, mainly for physical activity level and quality of life (Table 1). Conclusion The interventions are feasible and acceptable to participants. The results of this trial indicate the potential clinical benefit of lifestyle educational intervention associated with exercise intervention for people with diabetes and prediabetes.