The Totalization agreement with Italy became effective on November 1, 1978. On January 1, 1986, a supplementary agreement with Italy became effective, but the supplementary agreement did not affect the coverage and tax provisions of the original 1978 agreement.

If both the U.S. and Italian social security systems cover a worker's employment or self-employment, beginning November 1, 1978, only one country's system will cover the worker's employment or self-employment. The agreement does not affect a worker's coverage prior to that date. If a worker had dually covered earnings before November 1, 1978 those earnings remain subject to social security taxation in both countries.