The aim of this investigation was to compare inhaled budesonide with oral prednisone in maintenance treatment of pulmonary sarcoidosis. A double-blind controlled study was performed in 40 patients with stage II or III pulmonary sarcoidosis. After initial systemic 6 weeks treatment with prednisone (40 reduced to 20 mg daily) patients were allocated either to the systematically (S) or topically (T) treated group. S patients continued with 10 mg prednisone daily, T patients were given inhaled budesonide 1.6 mg daily. The progress of treatment was assessed by serial radiography, spirometry, serum Angiotensin Converting Enzyme (ACE) activity and plasma cortisol levels. All patients completed the 12 months treatment. Using the numerical score to assess changes on the chest radiograms S patients improved by 1.7 +/- 0.66 points; T patients improved by 1.15 +/- 0.81 points. Spirometric changes were not statistically significant. Serum ACE fell from 107 +/- 51 U/L in the S group and 92 +/- 40 U/L in the T group to 46 +/- 11 U/L and 38 +/- 21 U/L respectively during the initial phase of treatment. In the maintenance phase ACE levels remained lower than the initial ones in both groups. Morning plasma cortisol levels studied in 10 patients (5 in each group) decreased significantly during the initial phase. Thereafter cortisol levels remained low in the S patients returning to the lower limit of normal values in the T patients. We conclude that inhaled budesonide may be a safe and effective alternative to oral steroids in the maintenance treatment of pulmonary sarcoidosis especially in the early stage of the disease.