Acutely ill asthmatic patients treated in the usual fashion in an emergency room setting and discharged within six hours were studied to determine whether therapy with a single injection of a repository corticosteroid (methylprednisolone sodium acetate) could be as effective as a tapering course of oral corticosteroids in decreasing asthma symptomatology and relapse within seven days. Seventeen patients (18 episodes of asthma) formed the study population. Eight episodes occurred in patients who received depot methylprednisolone (group 1) and ten episodes in patients who received oral corticosteroid treatment (group 2). All patients in both groups improved following emergency room treatment. Relapse occurred in two of ten patients in group 2 and none in group 1. Symptoms attributable to asthma recurred in significantly more patients in group 2 than in group 1 (9 vs 0, p less than .01). Side effects from therapy with corticosteroids were rare. This study indicates that intramuscular repository corticosteroids are at least as effective as oral corticosteroids in the management of the acute asthmatic outpatient, with a distinct advantage with regard to patient compliance.