Linear growth was investigated with weekly knemometry in a population of 43 schoolchildren with mild asthma treated with inhaled budesonide. The design was a randomized, double-blind, parallel group study with three dose groups of 200, 400, and 800 micrograms of budesonide per day. Each dose group received budesonide for 8 consecutive weeks. Placebo was given for either 4 weeks before or after budesonide treatment. Twelve children in the 200-micrograms group, 14 in the 400-micrograms group, and 12 in the 800-micrograms group completed the 12-week study period. There was no significant difference in mean growth velocity among the three dose groups during placebo treatment. Compared with placebo (growth velocity: 0.39 mm/wk), mean lower leg growth velocity was reduced with 0.26 mm/wk (P less than .001, t = 5.0, df = 11; 95% confidence interval 0.14 to 0.37 mm/wk) in children treated with 800 micrograms of budesonide. There was no statistically significant difference in growth velocity between 200- or 400-micrograms budesonide treatments and placebo. These data indicate that inhaled budesonide can be safely used in doses up to 400 micrograms/d in schoolchildren with asthma.