Printed educational materials are widely used passive dissemination strategies to improve the quality of clinical practice and patient outcomes. Traditionally they are presented in paper formats such as monographs, publication in peer-reviewed journals and clinical guidelines. To assess the effect of printed educational materials on the practice of healthcare professionals and patient health outcomes.To explore the influence of some of the characteristics of the printed educational materials (e.g. source, content, format) on their effect on professional practice and patient outcomes. For this update, search strategies were rewritten and substantially changed from those published in the original review in order to refocus the search from published material to printed material and to expand terminology describing printed materials. Given the significant changes, all databases were searched from start date to June 2011. We searched: MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), HealthStar, CINAHL, ERIC, CAB Abstracts, Global Health, and the EPOC Register. We included randomised controlled trials (RCTs), quasi-randomised trials, controlled before and after studies (CBAs) and interrupted time series (ITS) analyses that evaluated the impact of printed educational materials (PEMs) on healthcare professionals' practice or patient outcomes, or both. We included three types of comparisons: (1) PEM versus no intervention, (2) PEM versus single intervention, (3) multifaceted intervention where PEM is included versus multifaceted intervention without PEM. There was no language restriction. Any objective measure of professional practice (e.g. number of tests ordered, prescriptions for a particular drug), or patient health outcomes (e.g. blood pressure) were included. Two review authors undertook data extraction independently, and any disagreement was resolved by discussion among the review authors. For analyses, the included studies were grouped according to study design, type of outcome (professional practice or patient outcome, continuous or dichotomous) and type of comparison. For controlled trials, we reported the median effect size for each outcome within each study, the median effect size across outcomes for each study and the median of these effect sizes across studies. Where the data were available, we re-analysed the ITS studies and reported median differences in slope and in level for each outcome, across outcomes for each study, and then across studies. We categorised each PEM according to potential effects modifiers related to the source of the PEMs, the channel used for their delivery, their content, and their format. The review includes 45 studies: 14 RCTs and 31 ITS studies. Almost all the included studies (44/45) compared the effectiveness of PEM to no intervention. One single study compared paper-based PEM to the same document delivered on CD-ROM. Based on seven RCTs and 54 outcomes, the median absolute risk difference in categorical practice outcomes was 0.02 when PEMs were compared to no intervention (range from 0 to +0.11). Based on three RCTs and eight outcomes, the median improvement in standardised mean difference for continuous profession practice outcomes was 0.13 when PEMs were compared to no intervention (range from -0.16 to +0.36). Only two RCTs and two ITS studies reported patient outcomes. In addition, we re-analysed 54 outcomes from 25 ITS studies, using time series regression and observed statistically significant improvement in level or in slope in 27 outcomes. From the ITS studies, we calculated improvements in professional practice outcomes across studies after PEM dissemination (standardised median change in level = 1.69). From the data gathered, we could not comment on which PEM characteristic influenced their effectiveness. The results of this review suggest that when used alone and compared to no intervention, PEMs may have a small beneficial effect on professional practice outcomes. There is insufficient information to reliably estimate the effect of PEMs on patient outcomes, and clinical significance of the observed effect sizes is not known. The effectiveness of PEMs compared to other interventions, or of PEMs as part of a multifaceted intervention, is uncertain.