Autologous iliac crest bone graft (ICBG) has long been considered the gold standard for the treatment of long bone non-unions due to its inherent osteogenic, osteo-inductive, and osteoconductive properties . However, harvesting ICBG is not without drawbacks. Donor site morbidity such as chronic pain, hematoma, infection, and gait disturbance has been reported in up to 20%-30% of patients, along with limitations in the volume of graft that can be safely harvested . In an effort to mitigate these challenges, biologic alternatives like Bone Marrow Aspirate (BMA) combined with cancellous allograft have gained attention. BMA is a rich source of mesenchymal stem cells (MSCs), hematopoietic stem cells, and growth factors such as bone morphogenetic proteins (BMPs) that contribute to osteogenesis. Fresh frozen cancellous allograft provides an osteoconductive scaffold but lacks viable cells and growth factors. When combined with BMA, it is hypothesized to mimic the biological properties of autograft while avoiding donor site complications. Despite promising early results in few studies, there is still a paucity of comparative studies evaluating the effectiveness of BMA with allograft against autologous ICBG in managing long bone delayed unions and non-unions. This study aims to bridge that gap by prospectively comparing the clinical and radiological outcomes between these two techniques.