BACKGROUND Long-acting beta-agonists and inhaled corticosteroids have both been recommended in guidelines for the treatment of chronic obstructive pulmonary disease. Their co-administration in a combined inhaler is intended to facilitate adherence to medication regimens, and to improve efficacy. Two preparations are currently available, fluticasone/salmeterol (FPS) and budesonide/formoterol (BDF). OBJECTIVES To assess the efficacy of combined inhaled corticosteroid and long-acting beta-agonist preparations, compared to inhaled corticosteroids, in the treatment of adults with chronic obstructive pulmonary disease. SEARCH STRATEGY We searched the Cochrane Airways Group Specialised Register of trials. The date of the most recent search is April 2007. SELECTION CRITERIA Studies were included if they were randomised and double-blind. Studies compared combined inhaled corticosteroids and long-acting beta-agonist preparations with the inhaled corticosteroid component. DATA COLLECTION AND ANALYSIS Two reviewers independently assessed trial quality and extracted data. The primary outcome were exacerbations, mortality and pneumonia. Health-related quality of life (measured by validated scales), lung function and side-effects were secondary outcomes. Dichotomous data were analysed as fixed effect odds ratios (OR), and continuous data as mean differences and 95% confidence intervals (CI). MAIN RESULTS Seven studies of good methodological quality met the inclusion criteria randomising 5708 participants with predominantly poorly reversible, severe COPD. Exacerbation rates were significantly reduced with combination therapies (Rate ratio 0.91; 95% confidence interval 0.85 to 0.97, P = 0.0008). Data from two FPS studies indicated that exacerbations requiring oral steroids were reduced with combination therapy. Data from one large study suggest that there is no significant difference in the rate of hospitalisations. Mortality was also lower with combined treatment (odds ratio 0.77; 95% confidence interval 0.63 to 0.94). Quality of life, lung function and withdrawals due to lack of efficacy favoured combination treatment. Adverse event profiles were similar between the two treatments. No significant differences were found between FPS and BDP in the primary outcomes, but the confidence intervals for the BDP results were wide as smaller numbers of patients have been studied. AUTHORS' CONCLUSIONS Combination ICS and LABA significantly reduces morbidity and mortality in COPD when compared with mono component steroid. Adverse events were not significantly different between treatments, although evidence from other sources indicates that inhaled corticosteroids are associated with increased risk of pneumonia. Assessment of BDF in larger, long-term trials is required. Dose response data would provide valuable evidence on whether efficacy and safety outcomes are affected by different steroid loads.