Anemia and leukopenia have been reported in sarcoidosis. In order to characterize the prevalence and association with disease activity, 75 patients with active pulmonary sarcoidosis were studied. One or more hematologic abnormalities were identified in 87% of patients studied. Anemia was present in 21 patients (28%), and bone marrow examination in 17 anemic patients revealed noncaseating granulomas in 9 patients and absent iron stores in 8 patients. The bone marrow aspirates did not show characteristics seen in other anemias of chronic disease, such as tuberculosis. In the majority of unexplained anemia cases, hemoglobin levels normalized with prednisone treatment. Forty-one of 75 patients (55%) had lymphopenia. Anemia found in patients with active sarcoidosis was associated with noncaseating granulomas in the bone marrow and an improvement with steroid therapy.