Objective: This long-term prospective study was conducted in African Americans with persistent asthma to examine the safety and effectiveness of the combination of the inhaled corticosteroid, fluticasone propionate (FP), and the long-acting beta-agonist, salmeterol, compared with FP alone. Research and design methods: This was a randomized, double-blind, parallel group, multi-center trial in adolescent and adult subjects ≥12 years of age symptomatic on a low dose of an inhaled corticosteroid (ICS). The study consisted of a 2-week screening period on low dose ICS; a 4-week open-label FP 250 mcg twice daily (BID) run-in; a 52-week double-blind period (FP/salmeterol [FSC] 100/50 mcg [n = 239] or FP 100 mcg [n = 236] BID), and a 4-week FP 250 mcg BID run-out period. Annualized exacerbation rate was the primary outcome for comparing the two treatments. Other measures of asthma control included peak expiratory flow, asthma symptoms, and albuterol use. Safety was assessed through adverse events. Results: Exacerbation rates were not significantly different in those treated with FSC 100/50 mcg (0.449 per year) compared with FP 100 mcg (0.529 per year, p = 0.169). When the per-protocol analysis was applied, the rates were 0.465 and 0.769 per year for FSC 100/50 mcg and FP 100 mcg, respectively. Treatment with FSC 100/50 mcg provided statistically greater improvements in lung function measures and nighttime awakenings (p ≤ 0.050) and demonstrated numerically lower daily symptoms (p = 0.216) and albuterol use (p = 0.122). Two subjects treated with FSC 100/50 mcg were hospitalized for an asthma exacerbation compared to three treated with FP 100 mcg. The overall incidence of adverse effects during double-blind treatment was similar between the FSC 100/50 mcg and FP 100 mcg treatment groups (61% and 68%, respectively). Frequent study visits were required of subjects during this long-term study, and it remains unknown whether this intervention may affect generalizability. Conclusion: In this large, prospective study among African Americans with asthma, the addition of salmeterol to FP resulted in a similar low rate of exacerbations and improved other markers of asthma control. Both FSC 100/50 mcg and FP 100 mcg were well-tolerated, and the overall safety-profiles were similar over 1 year of treatment. © 2008 Informa UK Ltd All rights reserved.