In recent years I have been engaged in research in the social anthropology of religion. In the course of investigating the changing religious beliefs and practices of Jewish immigrants in Israel from rural Tunisia and Morocco I initially sought to conceptualize the phenomena encountered in terms of 'secularization'. This study is a consequence of the problems that arose. 1 The first section of this paper discusses some of the general problems inherent in the sociological use of the term 'secularization' and of the closely related Church-Sect typology. The second section suggests an approach to the study of religious change which attempts to solve the problems that have been raised. Finally, the third section presents a casestudy to illustrate the approach.The consideration of phenomena of religious change in the light of the Church-Sect typology and of the term 'secularization' is very common in sociological literature. Initially, Troeltsch (1931, first published in 1912 conceived Church and Sect as two distinct and opposed types of religion, in the doctrinal as well as in the organizational senses. The universe of religions that Troeltsch sought to illuminate through these concepts was composed of contemporary and of past religious groups of Christian Europe. As a result of the subsequent work of scholars such as Niebuhr (1929) and Pope (1942), attention was drawn to much new data on the recent American religious scene, and Troeltsch's categories if they were to remain useful in the conceptualization of empirical data, had to be re-