Bone marrow necrosis has been regarded as a rare entity in specimens obtained from living patients and has been associated with poor prognosis. In contrast, we believe that it is a commonplace finding in bone marrow specimens which is frequently overlooked and which occurs in patients with multiple acute and chronic disorders. It is postulated that bone marrow necrosis eventuates from vascular occlusion of small blood vessels as a result of a number of causes. When bone marrow necrosis is prolonged, it may be associated with the development of bone marrow fibrosis and serve as a predisposing lesion for idiopathic myelofibrosis. Additional investigation of this phenomenon is required to determine its usefulness in the diagnosis of disease states and its role in the pathophysiology of a number of disorders.