The following work is an examination of the allegation that there has existed a world-wide Jewish Conspiracy, by which it is said that Jews have taken various actions aimed at achieving world dominance. I have taken as my starting point the death of William of Norwich in 1144, following which Jews were first accused of haNing a conspiracy plan and I have ended with the present day Holocaust deniers. The work is divided into two sections. The first concerns the Religious Conspiracy, and deals with the accusations that Jews conspired to kill Christ through means of a substitute child, as in the cases of Ritual Crucifixion and the Blood libel, or by means of host and imag ge desecration; and secondly that Jews conspired to kill all Christians by means of mass poisoning. The second section deals with the Modem Conspiracy Theory and examines the processes that gave rise to the twentieth century forgery, The Protocols of the Learned Elders of Zion; the Conspiracy Theory in Germany, with emphasis on conditions that led to Hitlers attitude towards Jews; and finally examines the state of the Conspiracy Theory in the post-Holocaust world. Overall I attempt to discover just what causes an accusation as outrageous as the Conspiracy Theory to endure throughout history.