Beclomethasone dipropionate (BDP) and budesonide (BUD) are commonly prescribed inhaled corticosteroids for the treatment of asthma, Fluticasone propionate (FP) is newer agent with greater potency in in-vitro assays.To compare the efficacy and safety of Fluticasone to Beclomethasone or Budesonide in the treatment of chronic asthma.We searched the Cochrane Airways Group trial register (January 2003) and reference lists of articles. We contacted trialists and pharmaceutical companies for additional studies and searched abstracts of major respiratory society meetings (1997 to 2003).Randomised trials in children and adults comparing Fluticasone to either Beclomethasone or Budesonide in the treatment of chronic asthma. Two reviewers independently assessed articles for inclusion and methodological quality.One reviewer extracted data. Quantitative analyses were undertaken using RevMan analyses 1.0.1.48 studies (11,479 participants) met the inclusion criteria. Methodological quality was variable. When compared at a FP:BUD/BDP dose ratio of 1:2, fluticasone produced a significantly greater FEV1 (Weighted Mean Difference (WMD) 0.11 litres, 95% Confidence Interval (CI) 0.01 to 0.20 litres), morning PEF (WMD 13 L/min, 95%CI 5 to 22 L/min) and evening PEF (WMD 11 L/min, 95%CI 1 to 20 L/min). This applied to all drug doses, age groups, and delivery devices, although subgroup analyses suggested that the relative benefit of FP may be greater in more severe patients treated with higher doses of inhaled corticosteroid. No difference between fluticasone and beclomethasone or budesonide were seen for trial withdrawals (Peto OR 0.76, 95%CI 0.53 to 1.09). Symptoms and rescue medication use were widely reported but few trials provided sufficient data for analysis. A higher likelihood of pharyngitis (Peto Odds Ratio 2.16; 95% CI 1.43 to 3.24) was apparent when patients were treated with fluticasone at twice the dose of BDP/BUD, although there was unexplained heterogeneity in this effect between trials. There was no difference in the likelihood of oral Candidiasis. Plasma cortisol and 24 hour urinary cortisol were measured frequently but data presentation was limited.Fluticasone given at half the daily dose of beclomethasone or budesonide leads to small improvements in measures of airway calibre, but it appears to have a higher risk of causing side-effects when given at the same daily dose.