Depression and grief are mostly manifested as comorbid disorders in elderly adults and are associated with negative consequences in elderly people’s physical and mental health in addition to poorer response to medicinal and psychological treatments. The aim of this study was to investigate the effectiveness of psychotherapy based on improving quality of life (QoL) on the symptoms of grief and depression of the elderly women residents of nursing homes in Isfahan. This semi-experimental study was conducted on two groups (experimental group=14 and control group=15) using a pretest-posttest design. Six 90-minute sessions (once a week) of group therapy based on improving QoL were performed for the experimental group. The questionnaires of grief experience and depression were completed by two groups in the pretest and posttest stages. Data were analyzed by SPSS 16 using MANOVA and ANOVA. Based on the results of MANCOVA and ANOVA, the experimental group's post-test scores of depression and grief decreased compared to the control group's scores and this therapy was effective in the terms of statistics. According to the results of this study, it can be said that this therapy has been effective in improving the symptoms of grief and depression among elderly women and can be efficient as a way to improve the QoL and treat the mental disorders in the elderly.