© 2020 European Foot and Ankle SocietyBackground: Impaired wound healing is a major cause of morbidity in diabetic patients by causing chronic ulcers. This study aimed to investigate the safety and outcomes after intralesional allogeneic adipose-derived mesenchymal stem cells injection in chronic diabetic foot ulcers. Methods: Twenty patients (12 male and eight female) were involved in the study. We randomized the patients into two groups of 10 patients each. The study group was treated with allogeneic adipose-derived mesenchymal stem cells injection with standard diabetic wound care. The control group received only standard diabetic wound care. Patient demographics, wound characteristics, wound closure time, amputation rates and clinical scores were evaluated. Results: The mean age was 57.3 ± 6.6 years. The mean follow-up duration was 48.0 (range, 26–50) months. Wound closure was achieved in 17 of 20 lesions (study group, 9 lesions; control group, 8 lesions; respectively). The mean time to wound closure was 31.0 ± 10.7 (range, 22–55) days in the study group, 54.8 + 15.0 (range, 30–78) days in the control group (p = 0.002). In three patients, minor amputations were performed (one patient in study group; two patients in the control group, p = 0.531). There was a significant difference between groups in terms of postoperative Short Form 36- physical functioning (p = 0.017) and Short Form 36-general health (p = 0.010). Conclusion: Allogeneic adipose-derived mesenchymal stem cells injection was found to be a safe and effective method with a positive contribution to wound-healing time in the treatment of chronic diabetic foot ulcers.