Purpose: The purpose of this study was to identify the effects of patients’ use of dementia day care centers by comparing cognitive function, depression, activity of daily living (ADL) and postural balance in users and non-users. Methods: Participants in this descriptive study were 72 dementia patients who had started using dementia day care centers, and 33 dementia patients who received home visiting service irregularly, instead of using the centers. Data were collected for ADL, instrumental activity of daily living (IADL), cognitive function, depression, and postural balance. Data were analyzed using SPSS/WIN 25.0 program. Results: The mean age of the participants was 78.8±5.95 years and 73.3% of them were women. There was no significant difference in age, gender and cognition scores between users and non-users. The statistically significant variables predicting cognitive function after 3 months were cognitive function at the beginning and use of a day care center. Depression score at the beginning and use of a day care center significantly predicted depression. ADL scores at the beginning, dementia day care center use, and dementia type also significantly predicted ADL scores. IADL scores at the beginning and marital status significantly predicted IADL scores. Conclusion: According to the results, elders regularly using dementia day care showed a delay in cognitive decline, a lessening of depression, and improved activities of daily living. Therefore, there is a need to increase day care centers for people with dementia and to encourage to use a daycare center is recommended.