As the media attention society on the world climate change, interest in the environment and social impact has increased. This has in turn made even more companies choose to maintain a sustainability report that contains the three aspects of economic, environment and social impact. The demand for sustainability reports has increased among stakeholders. It has made the companies that establish this form of reports experienced economic benefits. The sustainability report than became a useful way to compete among businesses. Since accounting has become a competitive tool, it has led many companies to describe the sustainability report in flattering terms to make the corporate brand stronger. The companies stakeholders wish to rely on the work that the company are supposed to do and this is where the role of auditors come in, to review and provide guidance on designing the report. The area is relatively new and a need for standards in the audit of the sustainability report has increased, there for the interest to investigate the auditor´s review process has occurred. Our main purpose of this study is to analyze and describe what the review process of the sustainability report looks like and how auditors apply the standards and guidelines contained within the subject.   We have chosen to apply a qualitative research strategy when we want to analyze how our respondents experience a given situation, how the auditors feel that the review process look like and what standards are in the area. Considering to this we have chosen the case study as research design, since we want to create an understanding of a specific situation. For the collection of data telephone interviews were made with auditors in the four auditing firms in Sweden; Deloitte, Ernst&Young, KPMG and PwC. The auditors interviewed are specialists in the review of sustainability reports.   Our conclusion is that the review process in the sustainability report is mostly similar to the financial audit. It is a process that generally includes the steps of planning, execution and reporting that is based on FAR´s recommendation RevR6. In situations where the recommendation is not providing enough support the auditors turn to their own audit methodology, which contains more detailed tools and models. We have also determined that GRI is the most common guidelines when firms establish a sustainability report. These are the guidelines the auditors review against at review assignments.   Keywords: Review process, sustainability report, audit, RevR6 and GRI.