Evaluated the contribution of several cognitive factors (tolerance of ambiguity, impermeability of present belief system, and cognitive quest) and emotional factors (perception of childhood relationship with parents, and childhood and adolescence stress and trauma) in precipitating religious conversion. Ss were 40 religious converts (aged 20–40 yrs) from 4 religious groups (Jewish, Catholic, Bahai, and Hare Krishna) and 30 age-matched religiously affiliated nonconverts (Jewish and Catholic). Converts' present belief systems were judged as more impermeable; but contrary to the cognitive hypotheses, the groups did not differ on several measures of tolerance of ambiguity and in degree of cognitive quest during adolescence. Emotional factors were more closely associated with religious conversion. Converts' perceptions of their parents were markedly more negative, and incidence of father absence was higher in the convert sample. Converts reported more traumatic events during childhood and described their childhood and adolescence as unhappy. In the interview with converts, personal stress was also reported more often than cognitive quest as characterizing the 2-yr period preceding conversion and as involved in the immediate consequences of conversion. (23 ref) (PsycINFO Database Record (c) 2016 APA, all rights reserved)