Given the prevalence and huge impact of cancer on the life of the child and the family, it has become one of the most important chronic diseases that emerge during childhood. The results of extensive studies have indicated high prevalence of depression, anxiety and exposure to chronic stress in parents, especially mothers, of children with cancer. The present study was conducted to investigate the impact of maternal Narrative writing on depression, anxiety and stress. The present quasi-experimental study was performed on 62 mothers of children with stem cell transplantation cancer using pre-test and post-test single-group design; DASS-21 anxiety and stress depression questionnaire was used to collect required data. In the implementation process, the Narrative therapy was performed during one week, from the third to tenth day of admission after completing the DASS-21 questionnaire by the mothers; finally, the DASS-21 questionnaire was evaluated again after one week. Based on the results of the present study, there was a significant difference between the pretest and post-test scores of depression, anxiety and stress after the intervention (P <0.001); additionally, Narrative therapy decreased depression, anxiety and stress of mothers significantly. The findings of the present study showed that Narrative writing can be used as an effective, simple and cost-effective way to confront and cope with negative events in transplantation centers; it, also, can function as a complementary therapy, along with medical therapies.