[Purpose] The purpose of this study was to evaluate the effects of mental practice on stroke patients’ upper extremity function and activities of daily living (ADL). [Subjects and Methods] In this study, 29 stroke patients were randomly assigned to two groups: an experimental group (n=14) and a control group (n=15). The experimental group performed 10 minutes of mental practice once a day, 5 days a week for 2 weeks in combination with conventional rehabilitation therapy. For the control group, general rehabilitation therapy was provided during the same sessions as the experimental group. The Action Research Arm Test (ARAT) and the Fugl-Myer assessment (FMA) were used to measure upper extremity function, and the Modified Bathel Index (MBI) was used to measure daily activity performance. [Results] After the intervention, the mental practice group showed significant improvements in upper extremity function on the affected side and ADL scores compared to the control group. [Conclusion] The results of this study demonstrate mental practice intervention is effective at improving stroke patients’ upper extremity function and daily activity performance. In follow-up studies, securing a greater number of experimental subjects, and evaluation of the intervention’s therapeutic durability are required.