Objective : The purpose of this study was to investigate the effects of task-oriented activities on self efficacy, activities of daily living skills, and quality of life in patients with dementia. Method : Twelve patients with dementia were participated for one month period of the experiments ; the interventions were given five times a week for four week, performed thirty minutes once a day. Self-efficacy was evaluated by Self-Efficacy Scale(SES) and ADL was assessed by Functional Independence Measure (FIM) and quality of life were by Geriatric Quality Of Life-dementia (GQOL-D). The data was analyzed using the statistical program SPSS version 20.0. Intervention results was paired t-test and Pearson correlation coefficient. Result : First, Scores of Self-Efficacy Scale(SES) were significantly increased(p< .001). Second, Scores of FIM were significantly increased(p< .001). Third, Scores of Geriatric Quality Of Life-dementia (GQOL-D) were significantly increased(p< .001). Conclusion : This study indicated that the task-oriented approach program may affect on self-efficacy, activity of daily living skills, and quality of life for patients with dementia. In conclusion, the findings of this study indicated that the task-oriented approach program can be useful for patients with dementia. Further studies, such as controlled trials, need to be followed to verify the effectiveness of the intervention.