Mutilating hand injuries are devastating injuries mostly associated with high costs to society due to the resulting disabilities. These injuries present significant challenges in diagnosis, treatment, and follow-up compared to other trauma cases. Each case has different presentation due to mechanism of injury and it is not easy to give strict guidelines covering all types of injury. In mutilating hand injuries, the mechanism of injury must be thoroughly understood through detailed history taking. Debridement should be performed carefully yet aggressively to preserve as many functional anatomical structures as possible. The debridement of non-viable muscle reduces the risk of complications following revascularization. Bone reduction and fixation in mutilating hand injuries are critical steps and differ from the treatment of simple, closed, or open fractures. In most mutilating hand injuries, early or delayed flap closure is required to protect the exposed critical structures. Acute flap repair is rarely needed, but it is necessary in cases of large segmental soft tissue defects that leave vital structures exposed or in cases with defective distal circulation requiring a flow-through flap. The timing of tendon reconstruction is important and ideally should be done once adequate soft tissue coverage has been achieved. Nerves are often crushed, contaminated, or have significant tissue loss. Even in nerves with continuity, damage due to crushing or stretching can occur, and it may not always be possible to fully assess the degree of nerve injury macroscopically. Reconstruction of mutilating hand injuries is complex and difficult. Each case needs customized approach with good planning and timing of the operations. Understanding hand and wrist biomechanics and basic hand functions greatly contributes to the functional outcomes of repairs. The goal is to achieve at least a functionally usable hand. Experience under the light of biomechanical knowledge and microsurgical skills is needed to treat these devastating injuries. Injury to many functional systems needs a comprehensive approach for a functional results. The surgeon should consider the global hand function. The aim of the surgery should direct to restoring the function itself.