Based on a sample of Catholics, this study examines the common assertion that interfaith marriages have a secularizing effect on family members by assessing the effects of the respondent's and his/her parents' type of religious marriage on 11 measures of religious commitment. On 3 of these measures (orthodoxy, religious salience, and God's influence on life), offspring of Catholic-conservative Protestant marriages scored highest, followed by offspring of homogamous Catholic and Catholic-liberal Protestant marriages, respectively. In addition, Catholics married to non-Catholics scored lower on attending mass and receiving communion than Catholics in homogamous marriages. Contrary to the secularization hypothesis, however, most of the religiosity measures were unrelated to both respondent's and parents' marital type. The implications these findings have for certain theoretical ideas that suggest that mixed marriages weaken religious commitment are discussed.