Objective To examine the effect of computerised decision support systems (CDSS) on nursing performance and patient outcomes.Data sources 15 databases including Medline and CINAHL were searched up to May 2006, together with reference lists of included studies and relevant reviews.Review methods Randomised controlled trials, controlled clinical trials, controlled before and after studies and interrupted time series studies that assessed the effects of CDSS use by nurses in a clinical setting on measurable professional and/or patient outcomes were included.