Dose-response of formoterol via pressurized metered-dose inhaler (pMDI) has not been determined in asthmatic pediatric patients aged 6 to <12 years. This study was designed to assess the bronchodilating dose-response of three formoterol pMDI doses in children with stable asthma aged 6 to <12 years receiving twice-daily (b.i.d.) budesonide 160 micrograms. A U.S., multicenter, five-way crossover study compared single doses of formoterol, a long-acting beta-agonist, via pMDI (2.25, 4.5, and 9 micrograms) or dry powder inhaler (12 micrograms; active comparator) and placebo, with a 3- to 14-day washout period between doses. Budesonide pMDI 160 micrograms, an inhaled corticosteroid, was given b.i.d. throughout the study. Fifty-four pediatric patients (mean age, 9.2 years; mean asthma history, 6.1 years) were randomized. All formoterol doses showed significantly higher average 12-hour forced expiratory volume in 1 second (FEV1; area under the curve) versus placebo (primary efficacy). Formoterol pMDI 4.5 and 9 micrograms showed significantly greater average 12-hour FEV1 than formoterol 2.25 micrograms (p = 0.0007 and p = 0.0001, respectively). Formoterol also resulted in significant improvement in maximum FEV1 during the 12-hour treatment period (secondary efficacy) with formoterol 4.5-, 9-, and 12-microgram doses versus placebo and the formoterol 2.25-microgram dose. Bronchodilation was not maintained during the 12-hour dosing interval with formoterol 2.25 micrograms. No serious adverse events were reported. Formoterol pMDI showed generally dose-proportional pharmacokinetics to 9 micrograms, as determined by urinary excretion. Single doses of formoterol pMDI showed a dose-response, with formoterol 9 micrograms exhibiting a maximum response, in pediatric patients aged 6 to <12 years with persistent stable asthma maintained on b.i.d. budesonide pMDI 160 micrograms. Clinical trial NCT01136655, www.clinicaltrials.gov.