Twenty-three patients with systemic lupus erythematosus (SLE) and ischemic bone necrosis are reported. All patients had received corticosteroids prior to the onset of ischemic necrosis, although one patient had received none for 13 years previously. Nineteen (83%) patients had multiple bone lesions including the femoral heads in 21 (91%) which were bilaterally involved in 15. In addition, humeral heads were affected in seven patients and the tibial plateaus, in three. The most striking feature of this group was the high incidence of Raynaud's phenomemon present in 14 (61%) of the 23 patients. Furthermore, central nervous system involvement was present in 10 (43%) patients, more prominent in those without Raynaud's (67%) than in those with vasospasm (29%). Thus, 20 of the 23 patients, or 87%, evidenced vascular abnormalities either in the form of Raynaud's phenomenon and/or systemic vasculitis. The pathogenesis of ischemic bone necrosis is discussed. In SLE, vasospasm or vasculitis, or both, augmented by corticosteroid therapy, could impede the microcirculation and result in the ischemic lesion.