1. Although a number of personality variables have been identified by various authors as the determinants of religious behavior, independent of specific religious denomination, the results of the studies under consideration certainly appear to be inconsistent with such claims. It is suggested instead that the personality correlates of religious behavior vary with the specific religious denomination. 2. For most people religious belief and religious observance are acquired or learned in the socialization process. In a culture in which there is no social pressure to conform in relation to religious behavior (e. g., Israel in relation to religious belief), individual differences in adult religious behavior may be a result of certain personality differences. In the Israeli Jewish sample a number of personality variables were found to covary with religious belief and/or observance. Religious belief and observance, however, were also highly significant sources of variance in subjects' values. These value differences probably influence the what and how of the socialization process which in turn may be responsible for some-although probably not all-of the personality variables associated with religious behavior. 3. In cultures which are characterized by strong social pressure in relation to religious conformity, e. g. the culture represented by our United States Protestant sample, the religious behavior of many individuals will be a result of their need to conform rather than other personality variables directly related to their religious behavior as such. Thus in the United States Protestant sample conformity and variables associated with it were the only significant sources of variance in subjects' religious behavior. The results of our studies indicate the importance of differentiating between religious belief and observance which is merely the result of social conformity and religious belief and observance which is also the result of other variables which are more directly related to religious behavior as such. Presently we are in the process of constructing instruments to measure these two types of religious behavior. 4. Finally, it is suggested that in trying to discover the determinants of individual differences in religious behavior there has been too much emphasis on motivational variables and not enough on environmental factors. A social learning model may be the best suited for the investigation of the sources of individual differences in religious behavior.