In many patients with stroke, trunk stabilization and balance are decreased. Trunk stabilization and balance are important to perform posture control and functional movement. This study investigates the effects of task-orientated training with the abdominal drawing-in maneuver in a sitting position on trunk control, balance, and activities of daily living in patients with chronic stroke. The study design is a randomized controlled trial. Thirty-eight patients with chronic stroke participated in this study. The task-oriented training combined with the abdominal drawing-in maneuver group (n = 13), the task-oriented training group (n = 13), and the control group (n = 12) received traditional physical therapy. Three groups participated in a total of 20 sessions, four times a week for five weeks. After the five-week training period, trunk control, balance, and activities of daily living were assessed. The task-oriented training combined with the abdominal drawing-in maneuver group demonstrated significant improvements in trunk control, balance, and activities of daily living compared to the task-oriented training and control groups (p < 0.05). These results have implications for improving trunk control, balance, and activities of daily living for patients with stroke, and support the integration of this training method into standard clinical practice.