Deflazacort, a synthetic oxazolone derivative of prednisolone with 0.84 times antiinflammatory effect of prednisolone, was reported to have less impairment of the bone formation-resorption rate than prednisolone. So deflazacort and prednisolone were compared in their influences in symptoms, pulmonary functions and biochemical parameters that reflect bone metabolism in steroid dependent chronic asthma(mean duration of previous oral steroid administration. 51months). The differences in the pulmonary function,symptom scores and peripheral eosinophil count from baseline to 3rd and 6th muth were not significant in both deflazacort(n = 10) and prednisolone(n=9) groups. Furthermore no significant difference was found in these parameters between deflazacort and prednisolone. Comparing with baseline, no significant difference in serum concentration of calcium, phosphate, total alkaline phosphatase, osteocalcin and urinary DPD/Cr was seen at 3rd and 6th month in both two groups. From basline to 6th month, the urinary Ca/Cr excretion was slightly decreased in deflazacort group(0.17+0.07 vs. 0.14+0.05) but we could not find statistical significance. As we compared deflazacort with prednisolone, there was no significant difference in serum concentration of calcium(p=0.8040), phosphate(p= 0.8896), total alkaline phosphatase(p=0. 2556), osteocalcin(p=0.6886), urinary DPD/ Cr(p=0.4004), and urinary Ca/Cr excretion ratio(p=0.1571). When the prednisolone was substituted for deflazacort with equipotent dosage in 5 out of 10 deflazacort administered patients, t,he concentration of serum total alkaline phosphatase was increased(49.2+7.4 vs. 55.8+2.8 IU/ml; p=0.062) and urinary Ca/Cr excretion ratio was decreased(0.1488+ 0.0531 vs. 0.0883+0.0728; p=0.080). Therefore we concluded that treatment with deflazacort might be an effective alternative to prednisolone treatment in steroid dependent chronic asthma. But we could not observe significant change in biochemical indices of bone turnover after prednisolone was substituted by deflazacort.