BackgroundType 2 diabetes is a chronic disease that is expanding at an alarming rate in the world. Research on individuals with type 2 diabetes showed that stressful life events cause problems in the effective management and control of diabetes. This study aimed at investigating the effect of a stress management intervention on blood glucose control in individuals with type 2 diabetes referred to Zarandeh clinic, Iran.MethodsIn this experimental study, 230 individuals with type 2 diabetes (179 female and 51 male) were enrolled and assigned to experimental (n = 115) and control (n = 115) groups. A valid and reliable multi-part questionnaire including demographics, Perceived Stress Scale, Coping Inventory for Stressful Situations, Coping Self-Efficacy Scale, and multidimensional scale of perceived social support was used to for data collection. The experimental group received a training program, developed based on the social cognitive theory and with an emphasis on improving self-efficacy and perceived social support, during eight sessions of one and a half hours. Control group received only standard care. Data were analyzed using SPSS 15 applying the t test, paired t-tests, Pearson correlation coefficient, and Chi square analysis. The significance level was considered at 0.05.ResultsBefore the intervention, the mean perceived stress scores of the experimental and control groups were 33.9 ± 4.6 and 35 ± 6.5, respectively, and no significant difference was observed (p > 0.05). However, after the intervention, the mean perceived stress score of the experimental group (26.7 ± 4.7) was significantly less than that of the control group (34.5 ± 7) (p = 0.001). Before the intervention, the mean scores of HbA1c in the experimental and control groups were 8.52 ± 1 and 8.42 ± 1.2, respectively, and there was no significant difference between the two groups. However, after the intervention, the results showed a significant decrease in glycosylated hemoglobin levels in the experimental group (p ≤ 0.05). Moreover, after the intervention, the result showed a significant difference between the mean scores of all aspects of Coping Inventory for Stressful Situations, coping self-efficacy, and perceived social support in the two groups (p < 0.05).ConclusionOur results suggested that the theory-based stress management intervention based on social cognitive theory may help to decrease stress and increase coping self-efficacy, stress management, perceived social support, and lead to a reduction in the glycosylated hemoglobin levels among patients with diabetes.