BACKGROUND New inhalation devices with improved lung delivery may allow the use of lower salmeterol doses for treatment of asthma. OBJECTIVE To determine the dose of salmeterol administered from a novel fluticasone propionate/salmeterol (FS) inhalation-driven, multidose dry powder inhaler (MDPI), which provides comparable efficacy and safety to FS dry powder inhaler (DPI). METHODS This double-blind, six-period crossover, dose-ranging study randomized 72 patients (ages ≥12 years; with persistent asthma and predose maximum forced expiratory volume in 1 second [FEV1] of 40-85% of the predicted normal) to treatment sequences (one dose per treatment), which consisted of FS MDPI 100/6.25, 100/12.5, 100/25, 100/50 μg; fluticasone propionate (Fp) MDPI 100 μg; and open-label FS DPI 100/50 μg. The primary efficacy variable was the baseline-adjusted FEV1 area under the curve over 12 hours after the dose (AUC0-12). Pharmacokinetics and tolerability were also assessed. RESULTS FEV1 AUC0-12 was significantly higher with all FS MDPI doses and FS DPI versus Fp MDPI (p < 0.0001), and with FS MDPI 100/50 μg versus FS DPI (least squares [LS] mean, 57.88 mL; p = 0.0017). FEV1 AUC0-12 trended toward higher efficacy with FS MDPI 100/25 μg (LS mean, 34.14 mL; p = 0.0624) and was comparable with FS MDPI 100/12.5 μg (LS mean, 3.42 mL; p = 0.8503) versus FS DPI. Salmeterol area under the plasma concentration-versus-time curve from time 0 to the time of the last measurable concentration (AUC0-t) for FS MDPI 100/12.5 μg and 100/25 μg was lower versus FS DPI 100/50 μg; AUC0-t for FS MDPI 100/50 μg was higher than FS DPI 100/50 μg. All FS MDPI doses were generally well tolerated. CONCLUSIONS All FS MDPI doses produced greater efficacy versus Fp MDPI. FS MDPI 100/12.5 μg demonstrated similar efficacy to FS DPI 100/50 μg with less salmeterol exposure. Clinicaltrials.gov NCT02139644, NCT02175771, and NCT02141854.