Purpose: This study aimed to examine the effects of mirror-neuron-system-based action observation physical training on improvements in upper extremity functions and daily living activities in chronic stroke patients. Methods: Ten chronic stroke patients were randomly selected. As a therapeutic intervention, along with conventional occupational therapy, the patients engaged in action observation physical training through repeated imitation practices after they viewed a video. The therapeutic intervention was implemented for 20 minutes, three times each week for eight weeks. A Manual Function Test (MFT) was conducted to compare upper extremity functions before and after the therapeutic intervention, and the Modified Barthel Index (MBI) was used to compare the ability to perform daily living activities. Results: Significant improvements in upper extremity motor functions and the ability to perform daily living activities were shown after the intervention. The subjects' left upper extremity motor functions and ability to perform daily living activities showed significant improvement after the intervention. Conclusion: The study's results indicate that action observation physical training based on the mirror neuron system improves chronic stroke patients' upper extremity motor functions and their ability to perform daily living activities. Therefore, action observation training has positive effects on the functional recovery of chronic stroke patients.