Methods: The pilot of study is situated on clinical trial research experiment, for two groups before and after intervention. Among 80 nursing students enrolled in Nursing and Midwifery school of Islamic Azad University Najaf Abad in 2013-2014 who trained in the field, all those who had poor expression were 36 subjects which measured with Adolescence Self-Assertiveness (ASA) scale and 24 subjects who want to enter to the research were separated randomly into experimental and control group. Experimental group consisting of Gestalt therapy, two-hours per session for 8 weeks, were trained. The control group did not receive the interventions. Therefore data analysis performed using the mean scores, paired t- test and intervention.

Results:In experimental group, the mean scores of assertiveness after intervention increased significantly (P<0/001). The mean scores of assertiveness of the control group showed no increase significantly (p=0/4). Comparison between mean score of assertiveness after and before of intervention in experimental group with control group was significant (p<0/005).

Conclusion: Gestalt therapy is effective on increasing of assertiveness. Thus, according to the results of this research, it may suggest that the methods of psychotherapy could be useful for ineffective components within enactment beliefs