Tapering regimens of oral steroids may be difficult or confusing for some patients. Repository steroids have been shown to be as effective as tapering oral doses in preventing relapse after emergency treatment. This study was undertaken to determine whether repository steroids are as effective as tapering oral steroids in preventing relapse after hospitalization for treatment of asthma. Twenty-six patients with acute exacerbations of asthma requiring treatment for 24 to 72 hours with parenteral steroids were randomized into two groups. Both groups received oral prednisone, 60 mg daily, when parenteral steroids were discontinued. At discharge, one group received intramuscular placebo and oral prednisone tapered over 8 days, and the other received 80 mg intramuscular methylprednisolone sodium acetate and oral placebo. At discharge and 2-week follow-up, patients were interviewed and examined, and spirometry results were obtained. There was little difference between groups in ratings of symptoms at discharge or follow-up. Both groups had less wheezing at follow-up than at discharge, though the improvement was significant only in the repository steroid group (p < 0.05). Mean forced expiratory volume in 1 second, forced vital capacity, peak expiratory flow rate improved at follow-up in both groups. No significant differences in outcome were found between the oral and repository steroid groups. (J ALLERGY CLIN IMMUNOL 1995;95:15-22.)