BACKGROUND: Assessments of long-term work disability are carried out by social insurance physicians (SIPs) and are little supported with evidence or instruments. Guidelines are hardly ever used in social insurance medicine. Developments in social insurance medicine might be slow as insurance is different from clinical medicine. AIMS: We explored the comparability of assessments in social insurance medicine in different countries and asked what guidelines were in official use. METHODS: Eighteen European countries were invited. A questionnaire on assessments practices was sent to national experts. A comparative table was presented to all contributors. Countries with guidelines were visited. Guidelines were categorised according to their purpose and their contents were compared. The results were presented to experts of the participating countries for validation. RESULTS: Fourteen countries participated. Functional capacity assessment was common. Guidelines for SIPs were reported to be officially in use in Germany, Ireland, the Netherlands and Switzerland. Twenty-two guidelines were medical and eleven were procedural. Medical guidelines mainly treated the same topics. Procedural guidelines were more variable. CONCLUSION: Assessment of work disability is comparable between countries. Medical and procedural guidelines should be further developed and tested on their value in practice. The procedural guidelines need to be published in a clear and comparable manner. The legal security of claimants would be endorsed by this. Germany and the Netherlands are most experienced and could take the lead in international development.