Objective. To evaluate the use of a noninvasive, low-frequency ultrasound device to treat residual burn wounds as an adjunct to regular wound dressing therapy. Methods. Nineteen patients with 38 residual wounds (served as self control) with an average post-burn duration of 94.6 days were recruited. Low-frequency ultrasound at 40 kHz was delivered in the ultrasonic group by a handheld probe, using normal saline as the irrigation medium. The control group had dressings changed with saline used as the coupling medium. Each wound was treated for 2 weeks (a total of 7 treatments; once every 2 days). Bacterial colony counts were done before the first and then after the fourth treatment. Serial color photographs were taken to evaluate the wound response at each visit. Healing time and percentage closure were determined. Results. Symptomatic relief (pain and odor reduction) was achieved in all patients. The healing percentage for the wounds treated with ultrasound was 100%. The healing rate in the treatment group was 84%, while the healing rate was 71.46% ± 31.06%; both were significantly higher compared to the control wounds (P < 0.01). The bacterial clearance rate in the ultrasound group (82.85 ± 19.13) increased significantly compared to the control group (35.55 ± 16.99). There were no major complications with the treatment, which was relatively painless. Conclusion. The application of low-frequency ultrasound treatment may heal residual burn wounds when a nonsurgical dressing change protocol has failed. The significant decrease in wound bioburden was definitely related to the use of the ultrasound treatment. No adverse reactions to the ultrasound treatment were found during the study.