OBJECTIVE To examine the clinical effectiveness of patient education models for adults with Type 2 diabetes. DATA SOURCES Electronic databases were searched from 2002 to January 2007. REVIEW METHODS A systematic review of the literature on educational interventions in diabetes was undertaken. This was an update of a previous systematic review. RESULTS Including studies identified in the previous systematic review, there were 13 published studies. Eight studies of education on multiple aspects of diabetes self-management were identified that provided education that was focused on a particular aspect of self-management. The quality of reporting and methodology of the studies was variable. Studies of multi-component educational interventions yielded mixed results. Some trials reported significant improvements on measures of diabetic control but others did not. Positive effects may be attributable to longer-term interventions with a shorter duration between the end of the intervention and the follow-up evaluation point. There may also be an effect of having a multi-professional team delivering the educational programme. Studies of focused educational interventions did not yield consistent results. Some effects were shown on measures of diabetic control in studies that focused on diet or exercise alone. Although the effects shown were generally small, those that were present did appear to be relatively long-lasting. This update review does not substantially alter the conclusions of the previous systematic review; for each outcome, the proportion of studies that demonstrated significant effects of education was similar. CONCLUSIONS Based on the evidence, it would seem that education delivered by a team of educators, with some degree of reinforcement of that education made at additional points of contact, may provide the best opportunity for improvements in patient outcomes. Educators need to have time and resources to fulfil the needs of any structured educational programme. There is also a need for education to have a clear programme at the outset. From the evidence reported it is unclear what resources would need to be directed at the educators themselves to ensure that they can deliver programmes successfully. Any future research should consider patient education within the context of overall diabetes care and as such follow guidelines for the development and evaluation of complex interventions. Good-quality, longer-term studies would be desirable, but these would require careful consideration around the nature of any control group. Information is needed to clarify the sensitivity of diabetes education programmes to the performance of the diabetes educators, in order to ensure success and cost-effectiveness of education programmes.