Five of 70 patients with systemic lupus erythematosus seen over a 5-year period had peripheral blood films suggestive of hyposplenism. Technetium-99m-sulfur colloid scans showed no splenic activity in three patients. One of these three patients, who had a spontaneous remission of persistent thrombocytopenia concurrent with the appearance of functional asplenia, had splenic atrophy shown by computed tomography; a second patient, who died of pneumococcal septicemia, was shown to have splenic atrophy with lymphocyte depletion at autopsy. The development of functional asplenia in the third patient has now, to date, had any obvious effect on her disease. In the two patients with normal scans, blood film findings returned to normal with treatment of the underlying disease. Polyvalent pneumococcal vaccine is recommended for patients with lupus erythematosus who have splenic atrophy.