Ongoing public discussion about the consequences of membership in new religious movements (NRMs) and the lack of studies concerning the relationship between the fit of the person with his or her NRM and well-being together call for a theoretically based investigation of the phenomenon. Hence, this German study on new members of three NRMs applied person-environment fit theory to investigate whether the fit between persons' needs for autonomy and relatedness, on the one hand, and the commensurate supplies of the groups, on the other, are related to well-being and mental health. The regression model following Edwards (1994) predicted satisfaction with religious affiliation, mental health, and depression, but not life satisfaction and anxiety. Results indicate that, for autonomy and relatedness, well-being measures tend to decrease as supplies exceed needs. Little support was found for a moderator effect of centrality of religiosity. Overall, findings encourage the application of person-environment fit theory to the study of membership in (new) religious groups and call for further research.a pps_ 181..201 L'actuel débat public sur les conséquences de l'adhésion à un nouveau mouvement religieux et l'absence d'études sur la relation entre l'adaptation de