Aims: Monthly breast self-examination (BSE) is one method for early detection of breast cancer. The aim of this study was to determine the effect of educational intervention based on the theory of planned behavior in promoting BSE of women in Gonabad, IRAN.
Materials & Methods: In this clinical trial study, 140 married women aged 20–49 years from Gonabad were chosen randomly and divided into control and experimental groups. Educational needs were determined and the curriculum was developed and presented in 5 sessions. BSE behavior was studied using the constructs of planned behavior theory before, immediately and 3 months after training. Data were analyzed by SPSS version 20, using  ANOVA, T-test student, Chi-square and multivariate analysis of variance and significant level was set at α=05.0
Findings: The mean age of the subjects was 37.27 ± 6.69 years. After intervention, the average score of BSE skill increased from 17.89 to 18.26 and the mean scores of theoretical constructs in the intervention group increased significantly (P<0.001). The effect of the educational intervention was evaluated three months later, but changes were not significant in the control group (P>0.05).
Conclusion: This study showed that educational intervention based on the theory of planned behavior was effective in promoting BSE behaviors. Therefore, it is recommended that educational interventions to be designed specifically for and consistent with the constructs of the theory of planned behavior.