In 1975 the United Nations General Assembly Resolution 3379 was passed. It stated that "zionism is a form of racism and racial discrimination."The UNGA Res 3379 was passed at the 2400th plenary meeting on 10 November 1975. (PDF) . Resolution 3379 was rescinded in 1991 by the Resolution 4686.The UNGA resolution 4686 was passed at the 74th plenary meeting on 16 December 1991 by a vote of 111-25-13. The text of the resolution is available here .
