Archival materials at the IISH are now accessible through Archives Portal Europe. The portal provides access to information on archival material from the inventories of hundreds of archival institutions in Europe. The user can search in 39,323,587 descriptive units linked to more than 141,000,000 digital objects from 397 institutions.
A search for "Kautsky", for instance, will give combined results in the collections of both IISH and Bundesarchiv Deutschland. In addition to a simple full text search, the Archives Portal Europe offers an advanced search concentrating on aspects such as dates as well as a navigated search for browsing through the archival material.
Digitized collections of the IISH are also available through Social History Portal and Europeana.
Archives Portal Europe is supported by the European Commission through the ICT PSP programme.