Background Many people have asthma, and for some their symptoms may be triggered by psychological factors. In addition compliance with medical therapy may have a psychological dimension. Therefore, psychological interventions aim to reduce the burden of symptoms and improve management of the disease. Objectives To assess the effectiveness of psychological interventions for adults with asthma. Search strategy The Cochrane Airways Group specialised register and PsycINFO were searched with pre-defined terms until September 2003. Selection criteria Randomised controlled trials published in any language assessing the effects of a psychological intervention compared with a form of control in adult participants were included in the review. Data collection and analysis Two reviewers assessed the relevance of abstracts identified by electronic searching and retrieved agreed studies for further scrutiny. The studies that met the inclusion criteria were assembled and data extracted. Main results Twelve studies were included in the review, however study quality was poor and sample sizes were frequently small. No meta-analysis could be performed due to the diversity of interventions and the outcomes assessed. Findings between studies were conflicting. This may have been due to the different types of interventions used and the deficiencies in trial design. Authors' conclusions This review was unable to draw firm conclusions for the role of psychological interventions in asthma due to the absence of an adequate evidence base. Large, well-conducted and reported randomised trials are required in this area, in order to determine the effects of these techniques in the treatment of asthma in adults.