The objective of this review was to identify, appraise and synthesise the best available evidence for the effectiveness of debriefing as it relates to simulation-based learning for health professionals. Simulation is defined as a technique used to replace or amplify real experiences with guided experiences that evoke or replace substantial aspects of the real world in a fully interactive manner. The use of simulation for health professional education began decades ago with the use of low-fidelity simulations and has evolved at an unprecedented pace. Debriefing is considered by many to be an integral and critical part of the simulation process. However, different debriefing approaches have developed with little objective evidence of their effectiveness. Studies that evaluated the use of debriefing for the purpose of simulation-based learning for health professionals were included. Simulation studies not involving health professionals and those conducted in other settings such as such as military or aviation were excluded. A review protocol outlining the inclusion and exclusion criteria was submitted, peer reviewed by the Joanna Briggs Institute (JBI) for Evidence Based Practice, and approved prior to undertaking the review. A comprehensive search of studies published between January 2000 and September 2011 was conducted across ten electronic databases. Two independent reviewers assessed each paper prior to inclusion or exclusion using the standardised critical appraisal instruments for evidence of effectiveness developed by the Joanna Briggs Institute. Ten randomised controlled trials involving various debriefing methods were included in the review. Meta-analysis was not possible because of the different outcomes, control groups and interventions in the selected studies. The methods of debriefing included: post simulation debriefing, in-simulation debriefing, instructor facilitated debriefing and video-assisted instructor debriefing. In the included studies there was a statistically significant improvement pre-test to post-test in the performance of technical and nontechnical skills such as: vital signs assessment; psychomotor skills; cardiopulmonary resuscitation; task management; team working; and situational awareness, regardless of the type of debriefing conducted. Additionally, only one study reported consistent improvement in these outcomes with the use of video playback during debriefing. In two studies the effect of the debrief was evident months after the initial simulation experiences. These results support the widely held assumption that debriefing is an important component of simulation. It is recommended therefore that debriefing remains an integral component of all simulation-based learning experiences. However, the fact that there were no clinical or practical differences in outcomes when instructor facilitated debriefing was enhanced by video playback is an important finding since this approach is currently considered to be the ‘gold standard’ for debriefing. This finding therefore warrants further research.