This chapter presents results about one of the questions that our research has focused from the beginning: religious change and deconversion. While in the Deconversion Study (2001-2005) we could use only cross-sectional data to estimate characteristics of deconverts in the U.S.A. and Germany, the analyses reported in this chapter are based on repeated surveys in three waves that allow the identification of concurrent and cross-time correlations—thus, open perspectives on the prediction of deconversion. Results indicate that, with difference between the three waves however, deconversion concurrently may correlate positively with openness to experience and negatively with consciousness, it may correlate also with mysticism and show concurrent correlations with truth of texts and teachings and self-rated religiosity. Cross-time correlations indicated as (negative) predictors of deconversion: self-rated religiosity, extraversion, agreeableness, environmental mastery, positive relations with others, purpose in life, self-acceptance, interpretive mysticism, and truth of texts and teachings. We conclude that low scores on variables for religiosity and religious cognition, but also personality and well-being variable that call for emotional compensation are predictors of deconversion.