Introduction:  Diabetes is a metabolic disease with several psychological outcomes. One of the important indicators of diabetes treatment and control is enhancement of psychological state of patients with diabetes. Therefore, this study aimed to investigate the effect of cognitive behavioral training on aggression and emotional maturity of female adolescents with type I diabetes for assessing a new approach of care and nursing.

Materials and Methods: This semi-experimental study had a pretest-post-test design. The study population included all the female adolescents with type I diabetes referred to health care centers of Shahr-e-Ray in 2015. Totally, 30 patients were selected by convenience sampling and randomly assigned to two equal groups. The experimental group received cognitive behavioral training during 10 sessions (each sessions 70 minute). The experimental and control groups completed the aggression and emotional maturity questionnaires at pre- and post-test. The data were analyzed through analysis of covariance in SPSS, version 19.

Results: There was a significant difference between the mean score of aggression and emotional maturity of the two groups, that is, cognitive behavioral training significantly decreased aggression and increased emotional maturity among female adolescents with type I diabetes (P≤0/01).

Conclusion: The results showed that cognitive behavioral training had a significant effect on aggression and emotional maturity of female adolescents with type I diabetes. Counselors and therapists can use this method to lower aggression and enhance emotional maturity.