Elderly seems to be one of the most important stages of individuals’ life. Considering the growing number of elderly population, it appears necessary to have didactic and therapeutic interventions that affect their psychological well-being significantly and increase their life expectancy. Therefore, this research aimed to determine the effectiveness of gestalt therapy on depression, self-differentiation, integrative self-knowledge and positive psychological characteristics of the elderly in Isfahan. Iran. It was a semi-experimental study with pretest-posttest and control group design along with a follow-up. The statistical papulation included all the elderly above 60-year old living in Isfahan. Two centers were selected among education retirees organization using convenience sampling and then, 40 elderly people were recruited purposefully according to eligibility criteria and assigned randomly into two groups of experimental and control with equal numbers in each group (20 members). The experimental group underwent gestalt therapy for 11 90-minute sessions, while the control group received no intervention during this period. Used to collect data were scales of elderly depression (Yesavage et al.), self-differentiation (Skowron & friedlander), integrative self-knowledge (Gorbani et al.) and positive psychological characteristics (Rashid). The collected data were analyzed using SPSS-23. The results of analysis of covariance (ANCOVA) demonstrated that gestalt therapy results in improvement of depression, self-differentiation, integrative self-knowledge and positive psychological characteristics in the elderly (p < 0.05). According to the findings of this research, gestalt therapy can be applied as an efficient pattern in counselling and psychotherapy centers to decrease depression and to improve self-differentiation, integrative self-knowledge and positive psychological characteristics for the elderly. References Afshari, A., Rezaei, R., & Dadras, F. (2019). 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