Objective: Diabetes is a multiorgan disease and considered a major health problem in different societies. One of the complications is the pain, particularly in the extremities resulting from a process known as diabetic foot ulcer. The diabetic patients are subjected to many complications because of foot ulcers, many of them similar to chronic wound disease or pressure ulcers (bed sore).. Among many tested materials and works for wound healing such as debridement, tissue oxygenation, and skin transplantation, platelet-derived compounds are allocated the pivotal position by investigators for tissue regeneration and shortening the wound healing process. Many platelet components are procured from platelet rich plasma (PRP) from whole blood donation. An additional purification step is required to diminish the volume and facilitate handling in some studies. It means that platelet concentrates (PCs) may be obtained leading to more concentrated platelets in lower volume. For better efficacy and comfortable utilization of the platelet, it is feasible to form the platelet gel and then apply on wound sites. The aim of this trial was to show the efficiency of platelet derived-cord blood on healing diabetic ulcers (wound reduction, rates of complete healing, infection prevention, Osteomyelitis) versus placebo (the standard care only) Materials and Methods: This study is a double blind randomized controlled trial to evaluate the positive effects of umbilical cord blood-derived platelet gel in 244 patients with diabetic foot ulcers. In this study all qualified patients (based on the inclusion and exclusion criteria) were randomly allocated into three study groups by a Stratified Permuted Block randomization method: group Received platelet rich plasma gel, group B (placebo) received platelet poor plasma gel, and group C received lubricant gel. Group A (interventional): application of 20-30 mL of gel from platelet rich plasma (PRP) Group B (placebo): application of 20- 30 mL of gel from platelet poor plasma (PRP) Group C (control): application of 20-30 mL of lubricant gel (used typically for sonography) All patients received weekly application above mentioned gels for 3 month (intervals: 1 week). Results: In this study we did not observe any significance among three therapeutic groups in wound recovery and tissue regeneration. In other words the platelet gel group demonstrated the same efficacy in comparison with platelet poor plasma (PPP) gel and the placebo group (p> 0.05). Conclusion: Although our results showed that growth factors in platelet granules may help the wound healing process and tissue regeneration, there are other factors that should be considered precisely for a statistically better clinical outcome. Another possible reason for not achieving the desirable effect is probably our diabetic patients did not respond sufficiently because of pathologic or genetic conditions.