Background: Cognitive impairments, which are common problems among the elderly people, account for a wide range of aging disorders. Group reminiscence can be used as a profitable therapeutic method for preventing cognitive-behavioral disorders in older adults. Therefore, we aimed to investigate the effect of group reminiscence on the cognitive status of elderly people.Methods: This study was a non-blinded randomized controlled trial. We enrolled 100 elderly people who were under the support of Ilam Welfare Organization, western Iran in 2013. Balanced block randomization method was used to randomize the participants into intervention and control groups.Elderly people in the intervention group participated in a group reminiscence program consisted of two one-hour sessions per week for 8 consecutive weeks. Data were collected using Mini Mental State Examination (MMSE). The questionnaire was completed four times by the participants; before, immediately after, two and three months after the intervention.Results: The mean±SD of cognitive status scores in the intervention group was 24.66±3.8 which increased to 25.02±3.67, 25.04±3.72 and 24.72±3.66 immediately after, two and three months after the intervention respectively. The results showed that the changes in the mean scores were statistically significant in the intervention group immediately after the intervention (P=0.001) and at second month (P=0.003) follow-ups. However, we found no statistically significant difference in the intervention group at the mentioned time intervals in this regards (P=1.000). Conclusion: We concluded that continuous programs of group reminiscence could improve cognitive status of elderly population.Trial Registration Number: IRCT201405147531N7