OBJECTIVE The changes and limitations that occur in the aging process effect people's adaptation to old age. This study aimed to assess the effect of reminiscence therapy on the adaptation levels of non-institutionalized elderly women to old age. METHODS We used a randomized controlled trial design. We conducted the study with 50 elderly women, including 27 women in the intervention group and 23 women in the control group. Study data were recollected by using an introductory information form, Mini-Mental State Examination (MMSE) and Assessment Scale of Adaptation Difficulty for the Elderly (ASADE). Reminiscence therapy was applied to the participants in the intervention group through individual sessions for 8 weeks by making house visits once a week. RESULTS At the end of reminiscence therapy made through weekly house visits, we compared the mean ASADE and MMSE scores of intervention and control groups and found that there was a statistically significant difference between the mean ASADE and MMSE scores of the participants in the intervention group (p < 0.05). CONCLUSIONS This study found that reminiscence therapy increased the elderly women's adaptation to old age and cognitive level.