Background: Determining the potential for bias present in randomised controlled trials is an essential part of the process in undertaking a Cochrane review. Many checklists and scales have been developed for assessing the quality of randomised controlled trials. One such system is the PEDro scale used for determining the potential for bias in randomised controlled trials contained in the PEDro database and OTseeker databases. PEDro (Maher et al., 2003) and OTseeker (Bennett et al., 2003) are freely accessible online databases of randomised controlled trials and systematic reviews of relevance to physiotherapy and occupational therapy respectively that periodically exchange content with the Cochrane Rehabilitation and Related Therapies Field database. Together, PEDro and OTseeker contain approximately 10,000 trials that have already been appraised for risk of bias independently by two people. Objectives: Given the large number of trials available through these databases that have already been appraised, a comparison with the new ‘Risk of bias’ tool introduced by The Cochrane Collaboration released this year with RevMan 5 is warranted to inform review authors undertaking reviews relevant to rehabilitation. Methods: The components and structure of both the Cochrane ‘Risk of bias’ tool and the PEDro scale were compared. Results: The PEDro scale contains eight items pertaining to internal validity including adequate randomisation, allocation concealment, blinding of participants, therapists and research personnel, incomplete outcome data, baseline similarity, and use of intention to treat analysis. In comparison, the ‘Risk of bias’ tool introduced by The Cochrane Collaboration contains a number of different domains including sequence generation, allocation concealment, selective outcome reporting, blinding, incomplete outcome data, and ‘other sources of bias’. On the surface there appears to be much in common, however important differences exist. This paper will provide detailed comparison of the risk of bias tool introduced by Cochrane with the PEDro scale. Conclusions: Although there are some significant differences between these two tools, methods being undertaken by the PEDro and OTseeker database teams to map the PEDro scale to the Cochrane ‘Risk of bias’ tool will improve the ability of review authors to make use of some of the substantial work already undertaken.