Social security in Switzerland has a long history stretching back to the mid-19th century.
As regards OASI and DI in particular, it was not until the 1920s that the legal basis was established which would allow such arrangements to be put in place. OASI saw the light of day in 1948, but it was not until 1960 that DI was created.
In the 1950s and 1960s, the economic boom in Switzerland saw huge numbers of workers being recruited from Italy and other neighbouring countries, to make up for the shortfall in local labour. In this context, bilateral agreements were concluded to regulate cooperation in the area of migration. In the 1960s, the agreements were renegotiated and supplemented with social security agreements, in particular in response to the need for labour in manufacturing.
Over time, the body of social security agreements concluded by Switzerland, in particular as regards OASI/DI, has grown and now covers some 50 countries.
See below for a list of documents forming the basis for international coordination on social security for Switzerland: