Introduction: Diabetes is a highly prevalent disease worldwide. Despite routine treatments, there is no effective treatment approach for patients with diabetic foot ulcers (DFUs). A new approach to reduce complications and control DFU is low-level laser therapy (LLLT). In the present study, we evaluated the therapeutic effects of LLLT on the symptoms of DFU patients. Methods: Sixty diabetic patients with DFU were included in this randomized clinical trial and were randomly allocated into two groups of laser (n=30) and control (n=30) with signed written consent. The LLLT group underwent visible and infra-red laser therapy and conventional medical treatment, while the control group received only conventional medical treatment. The total laser irradiation sessions of the patients were 20 sessions, (three sessions a week) and each session lasted for 30 minutes over the entire surface of the wound. The power density per session for each laser was calculated to be 35.65 mW/cm2 with an energy density of 64.17 J/cm2. Results: The mean area of ulcers in the LLLT group reduced significantly (P<0.001) from 441.7±365.5 mm2 before LLLT to 163.9±213.9 mm2 from the baseline up to the last session of LLLT, indicating a 62.99% reduction in mean ulcer area. In the control group, the mean ulcer area did not change significantly. Wagner's classification of the patients in the LLLT group reduced to lower grades significantly (P<0.01), while the classification moved towards higher grades in the control group (P<0.08). Conclusion: In this study, we showed the effectiveness of LLLT in the reduction of the surface and depth of DFUs. The results documented that patients experienced significant improvements in the healing of their foot ulcers after laser therapy. It is recommended that the LLLT be considered as a non-invasive method for the treatment of DFU patients.