Fungal studies were conducted on 35 patients with corticosteroid-dependent asthma (CSDA) and 20 asthmatics who had never received prednisolone. Candida albicans was repeatedly cultured from the sputa of 12 patients with CSDA. Isolation was more frequent in those patients who were receiving more than 10 mg prednisolone for more than six months. Nearly half of these patients demonstrated a positive immediate cutaneous reaction and precipitating antibodies against C. albicans. Although no pathological significance, beside colonization, could be attributed to this finding, it was felt that it would be prudent to restrict the daily dose of prednisolone to less than 10 mg, when administered for more than six moths. Two patients with allergic bronchopulmonary aspergillosis (ABPA), were identified, one from each group. The possibility of ABPA, however, remained open in two other patients with CSDA. It is probable that some patients with CSDA may be suffering from ABPA but characteristic features of the disease are masked by costicosteroid therapy, making it difficult to diagnose.