In this thesis, I would like to examine the adjustment process of new Jewish immigrants to the United States, and New York City in particular, during the Progressive Era (188Os to 1920). I intend to examine this process in the context of various theories, and the historical reality, of the establishment of American national ethnic patterns. I want to describe what long and arduous journey American ethnic groups had to lead toward the establishment of national ethnic patterns. The journey they passed through was always filled by cultural prejudice. On the other hand, it is also filled by the sensible attempt to overcome the problem of ethnicity. American society was a heterogeneous one in which consisted of immigrants and their descendants who came from various parts of the world. On one side, the heterogeneity of American society had caused the forming .of Cultural Pluralism. However, on the other side, the major part of American society- especially White Anglo Saxon Protestant- tried to assimilate the never-ending waves of new immigrants. The waves of immigrants before industrial period or during the year of 1800s to 1880 were mostly from West and North Europe. Therefore, in about three centuries, Anglo-Saxon values and cultures embedded firmly in American society. The White Anglo-Saxon Protestant (WASP) values were used as a model to assimilate the non-WASP. The WASP values were regarded as the real American ones and stood above stratified structure of other ethnic groups. Jewish ethnic was one of American ethnic groups who had settled in America since colonial period. The adjustment process of the old immigrants- those who came before industrial period of 1880 to 1920- did not create any serious problem. However, the great migration of new Jews- who came during industrial period- created a serious problem of adjustment process. Jewish principle of material pursuit was similar to that of Puritan society, the ancestor of American people. The middle class ethics possessed by the Jews were practiced without any obstacles in the land of America. That's why Jewish identity was always referred to the achievement of material success. By practicing middle class ethics, Jews of America achieved economic success. The economic stability was the important factor in establishing their strong social position in society. Their success in the economic sector enabled them to support other sectors, such as the founding of Jewish synagogues and schools, and other sectors that strengthened the identity of Jews. On the other hand, the success of Jews forced them to assimilate to American life and accept American values, especially when they want to succeed in dealing with their customers. Thus, they had to learn to speak English and wear suits, to learn and practice American cultural values. On the other hand, Jews strengthened their ethnic identity, but on the other they were influenced by Americanization process and more or less accepted American values. The adjustment that I describe in this writing is not the process of the adjustment itself, but the adjustment through four institutions that played an important role in the process. The four institutions of social and cultural life, religion, economy, and education were the factors that would describe and support Cultural Pluralism model.