The aim of the present study was to evaluate the prevalence of adrenal suppression and growth retardation in children using moderate doses of budesonide or fluticasone propionate. Seventy-five asthmatic children were randomly divided into three treatment groups: 30 to the fluticasone propionate (FP), 30 to the budesonide (BUD), and 15 to the cromone (CROM) group. FP doses were 500 microg/day during the first 2 months and 200 microg/day thereafter. The respective BUD doses were 800 and 400 microg/day. A low dose ACTH (0.5 microg/1.73 m2) test was performed before treatment and 2, 4, and 6 months later. The test was considered abnormal if the stimulated serum cortisol concentration was more than 2 SD lower than the pretreatment mean (<330 nmol/L). The low dose ACTH test was abnormal after both the high and low steroid doses in 23% of the children. At the 4 month measurement there were more abnormal tests in the BUD (n = 9) than in the FP (n = 5) group (P < 0.05). At that time also the stimulated concentration of serum cortisol was lower in the BUD than in the CROM group (P < 0.01), whereas the difference between the FP and CROM groups was not significant. During the study year the mean decrease in height SD score was 0.23 in the children treated with BUD, 0.03 in the children treated with FP, and 0.09 in the children treated with CROM; the difference between the BUD and FP groups was significant (P < 0.05). In conclusion, the low dose ACTH test revealed mild adrenal suppression in a quarter of the children using moderate doses of inhaled steroids. A FP dose of 200 microg/day caused less adrenal and growth suppression than did a BUD dose of 400 microg/day.