Seven children with asthma were included in a trial of recombinant interferon-alpha 2a (rIFN-alpha 2a). Patients received either 2 million U/m2 rIFN-alpha 2a (n = 4) or placebo (n = 3) three times a week for 4 weeks. Pulmonary function test, peak expiratory flow rates (PEFR), and clinical symptom scores were monitored throughout the trial. Serum interleukin-4, soluble low-affinity receptor for IgE Fc epsilon RII/CD23 (sCD23), and immunoglobulin E (IgE) levels were measured at the beginning of the trial, and at the second week, fourth week, and sixth week. Compared with placebo, rIFN-alpha 2a therapy did not result in a significant change in the above-mentioned parameters. Further studies with a larger number of patients are needed to draw firmer conclusions in regard to efficacy of rIFN-alpha 2a therapy in childhood asthma.