The scope of this article was to evalu-ate the effect of the behavioral group education program and telephone intervention in modify-ing psychological attitudes, enhancing empower-ment, and self-care practices aimed at improving clinical control in type 2 diabetes mellitus. It in-volved a randomized cluster clinical trial, carried out with 199 people with diabetes. In order to perform intragroup comparisons (final and ini-tial phases) and between groups with respect to the indices of the psychological attitude, empow-erment, self-care and glycated hemoglobin level variables, the Generalizing Estimating Equation (GEE) approach was used. In all analyses, a 5% significance level and 95% confidence interval were used. When compared to the CG, the IG showed a significant reduction in the mean values of glycated hemoglobin (95%CI:-1.49 to-0.45), a statistically significant increase in the change in psychological attitude scores (95%CI: 9.70 to 15.40), on the empowerment scale (95%CI: 0.81 to 2.72) and adherence to self-care practices (95%CI: 1.44 to 2.10) at the end of the study. The behavioral program proved to be capable of mod-ifying psychological attitudes, improving empow-erment, self-care practices and clinical control.