Background: Optimal therapy for many patients with persistent asthma requires control of both main components of this disease: inflammation and bronchoconstriction. Objectives: To compare the efficacy and safety of initiating maintenance therapy with an inhaled, long-acting beta(2)-agonist and an inhaled corticosteroid administered from a single device with that of the individual agents alone. Methods: A 12-week, randomized, double-blind study was conducted in patients 12 years and older with persistent asthma who were symptomatic while taking as-needed, short-acting beta(2)-agonists alone. Treatments were administered twice daily via the Diskus device: salmeterol, 50 mug; fluticasone propionate, 100 mug; or fluticasone propionate, 100 mug, with salmeterol, 50 mug. Results: Of 555 patients screened, 267 were randomly assigned to treatment. At end point, fluticasone propionate and salmeterol significantly increased predose forced expiratory volume in 1 second (FEV1) compared with salmeterol alone (0.51 +/- 0.05 L vs 0.38 +/- 0.04 L, P = .04). Fluticasone propionate and salmeterol significantly increased area under the serial FEV1 curve at treatment week 12 relative to predose FEV1 (baseline) on treatment day 1 (AUC(bl), 8.4 +/- 0.6 L/h; P less than or equal to .02) compared with salmeterol (6.2 +/- 0.5 L/h) and fluticasone propionate (7.0 +/- 0.6 L/h). Fluticasone propionate and salmeterol were significantly (P less than or equal to .02) more effective than the individual agents used alone in improving morning and evening peak expiratory flow rate and asthma symptoms. In addition, fluticasone propionate and salmeterol effectively reduced rescue albuterol use (P less than or equal to .04). All treatments were well tolerated. Conclusions: In patients symptomatic while taking short-acting beta(2)-agonists alone, initial maintenance treatment of the 2 main components of asthma, inflammation and smooth muscle dysfunction, with fluticasone propionate and salmeterol, 100 and 50 mug, administered via the Diskus results in greater improvements in overall asthma control compared with treatment of either component alone.