Background Reduction of lung inflammation is one of the goals of cystic fibrosis therapy. Inhaled corticosteroids are often used to treat children and adults with cystic fibrosis. The rationale for this is their potential to reduce lung damage arising from inflammation, as well as their effect on symptomatic wheezing. It is important to establish the current level of evidence for the risks and benefits of inhaled corticosteroids, especially in the light of their known adverse effects on growth. This is an update of a previously published review. Objectives To assess the effectiveness of taking regular inhaled corticosteroids, compared to not taking them, in children and adults with cystic fibrosis. Search methods We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register, comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. We requested information from pharmaceutical companies manufacturing inhaled corticosteroids and authors of identified trials. Date of most recent search of the Group's Trials Register: 15 August 2016. Selection criteria Randomised or quasi-randomised trials, published and unpublished, comparing inhaled corticosteroids to placebo or standard treatment in individuals with cystic fibrosis. Data collection and analysis Two independent authors assessed methodological quality and risk of bias in trials using established criteria and extracted data using standard pro formas. Main results The searches identified 34 citations, of which 26 (representing 13 trials) were eligible for inclusion. These 13 trials reported the use of inhaled corticosteroids in 506 people with cystic fibrosis aged between six and 55 years. One was a withdrawal trial in individuals who were already taking inhaled corticosteroids. Methodological quality and risk of bias were difficult to assess from published information. Many of the risk of bias judgements were unclear due to a lack of available information. Only two trials specified how participants Inhaled corticosteroids for cystic fibrosis (Review)