This article updates one published in The Guides Newsletter in January/February 1998 and reflects changing legislation in the workers’ compensation area and also in motor accident compensation. In the various Australian state and federal jurisdictions, impairment rating has become an important component of independent medical examinations, and in many areas, impairment guides have been adopted as a mandatory tool for assessing permanent impairment. For example, in the mid-1990s the state of Victoria established use of the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Fourth Edition, as the sole tool for evaluating impairment and continues to use this edition to the present time. Despite the publication of the AMA Guides, Fifth Edition, in 2000, the Motor Accidents Authority in New South Wales (NSW) continues to use the fourth edition, supplemented with the NSW Motor Accidents Authority Guidelines. In November 2001, Tasmania adopted the same guidelines that were being used by the NSW Motor Accidents Authority. Despite publication of the AMA Guides, Sixth Edition, in 2007, there has remained a general reticence in Australia to progress to use of this latest edition either as stand-alone impairment rating tools or an underpinning of the purpose-developed impairment guidelines already in place. A large number of Australian medical assessors have become used to the model based on the NSW WorkCover Guides for the Evaluation of Permanent Impairment, which interprets the AMA Guides, Fifth Edition.