All surgeons caring for patients with trauma to the extremities or practicing vascular surgery must be able to recognize and surgically treat compartment syndromes. Compartment syndrome (CS) results from a variety of etiologies with the final common pathway being increased compartmental pressure that exceeds the arterial inflow with resultant ischemia and necrosis. Failure to identify and treat compartment syndromes in a timely fashion is associated with preventable morbidity and mortality and is a common source of litigation. The diagnosis of CS is largely clinical, but measurement of compartment pressures may be useful in patients with equivocal findings or altered level of consciousness. Below the knee, the lower extremity is most commonly affected, followed much less frequently by the forearm, thigh, buttock, foot, and hand. This chapter will briefly review the pathophysiology, diagnosis, and relevant anatomy of CS of the extremities. The surgical treatment of CS of the extremities will be the major focus of this chapter with a practical step-by-step approach to fasciotomies of the lower leg, thigh, and forearm.