Background Reminiscence therapy is one of various interventions that can be made to protect and improve the mental health of the elderly. The aim of this study was to evaluate the effect of individual reminiscence therapy given during home visits on adaptation difficulties. Method This was a randomized controlled, single-blind study designed with a pretest-post-test and follow-up pattern. We divided the participants, 65 elderly people living in Isparta, Turkey, by simple randomization into intervention (31) and control (34) groups. Individual reminiscence therapy was applied to the intervention group participants for eight weeks during house visits once a week. The weekly topics of the reminiscence therapy included childhood, business life, married life, old items, holidays, traditional dishes, and songs and movies, and were all culture-specific. No intervention was applied to the control group. Study data were collected by using a Sociodemographic Data Form created by the researchers, the Assessment Scale of Adaptation Difficulty for the Elderly (ASADE), and the Nurses' Observation Scale for Geriatric Patients (NOSGER). Pretest, post-test, and follow-up data were collected at the individuals' homes in face-to-face interviews. Results After the eight-week course of reminiscence therapy, there was a significant decrease in the ASADE mean score for the intervention group (P = 0.003) and a significant increase for the control group (P < 0.001). Significant increases were also found in the mean NOSGER scores for the intervention (P = 0.039) and control (P < 0.001) groups; however, the score increase was higher for the control than for the intervention group. Also, there was a significant difference in the ASADE (P < 0,001) and NOSGER (P = 0.01) mean scores of the intervention and control groups. Conclusion This study found that individual reminiscence therapy decreased adaptation difficulties in the elderly.