It is well known that in the Hellenistic and Roman eras there were Jewish communities throughout the then civilised world. This study is devoted to the investigation of one part of the Jewish Diaspora, Asia Minor. In this area Jewish communities were established at a quite early date and seem to have flourished. The decrees given in Jewish Antiquities 14 and 16, which are largely from Asia Minor, were understood by Josephus as setting important precedents showing that the situation of the Jewish communities in Asia Minor was significant for Diaspora Judaism in general. From some time in the third century CE until the seventh century the community at Sardis owned the largest and most impressive synagogue yet discovered. Many other factors suggest that these communities have a significant place in the history of the Jewish Diaspora. Further, an understanding of the Jewish communities in Asia Minor is important for the study of early Christianity. Paul travelled extensively in Asia Minor, lived for a lengthy period in Ephesus, founded significant churches in the area, and engaged in debate with both Jew and Gentile there. It is therefore arguable that, in addition to the Jewish communities in Palestine, those in Asia Minor are an important context within which to view Paul's mission and theology. Other documents in the New Testament can also be located in Asia Minor, and it is to be hoped that a greater understanding of Jewish communities in this area will further elucidate these works.