To evaluate the long-term action of deflazacort (DF), a new calcium-sparing and bone-saving corticosteroid, in chronic sarcoidosis patients needing prolonged therapy. 40 patients with chronic histologically proved sarcoidosis requiring long-term corticosteroid therapy were treated with DF and followed for a mean period of 958 +/- 515 days (range 382-2, 068). The indication for giving corticosteroid therapy was pulmonary impairment in most (36), but also other events including hypercalcemia (2), kidney stones (5, 2 with recurrent colic), uveitis (2), lupus pernio (3), suspected heart impairment (5), hypersplenism (1), and other causes. Follow-up examination included serial ACE, chest x-ray, 67Ga lung scan, pulmonary function data, serum and urinary calcium levels. Eleven patients (UT group) were not receiving glucocorticoids when first seen at our clinic; 29 patients (PT group) were on therapy with glucocorticoids (27 wity prednisone, 2 with DF) for 870 +/- 1,128 days (range 27-4,310) In the PT group, DF maintained the good results previously obtained with prednisone; in this group, chest x-ray film showed improvement in 16 patients, 67Ga lung scan was better in 13, while worsening chest x-ray film findings in 1 and 67Ga lung scan in 2 was seen coincident with DF tapering. Respiratory function data showed a mild nonsignificant improvement. SACE decreased significantly from 114.6 +/- 38.7 to 91.5 +/- 37.9 nM/ml/min (p less than .05). In the UT group the results were better, as expected in a population where the action of corticosteroids did not influence the first observation. FVC increased significantly from 76.3 +/- 13.0 to 89.9 +/- 19.5 percent predicted (p less than .01); the 67Ga lung scan and chest x-ray film findings improved in all but 1 patient, and ACE dropped significantly (p less than .01) from 131.8 +/- 46.3 to 83.7 +/- 25.0. In both groups the side effects were mild, and only 2 patients discontinued the treatment, 1 for gastric ulcer, and the other for amenorrhea plus a 14 kg weight gain. One patient died of cancer, 9 discontinued treatment (5 because therapy was no longer necessary, 2 for the above described side effects, 2 for non-drug-related reasons), 4 dropped out and were last seen when taking DF 22.5, 18, 12 and 6 mg daily respectively. Twenty-six are continuing the drug on a long-term basis at the current mean daily dose of 12.1 +/- 7.3 mg (range 3-30). In a number of these, an attempt to discontinue DF resulted in a sarcoid relapse, and DF was restarted. DF is a good and safe approach to the long-term corticosteroid therapy of sarcoidosis.