Academic scientists in the United States are relatively nonreligious, at least compared to the general population, and some evidence suggests that the professional culture of academic science may foster perceptions of discrimination among scientists who are religious. We examine perceptions of religious discrimination among biologists and physicists in the United States. The analysis shows that Protestant, Muslim, and adherents of “other” traditions report higher rates of religious discrimination in both biology and physics relative to those who do not identify with a religion. Jewish and Catholic adherents report higher rates of discrimination in biology but not in physics. Most of the religious identity effects among biologists are not explained away by measures of beliefs, practices, or professional and demographic characteristics. On the other hand, religious identity differences in perceptions of religious discrimination among physicists are mediated by measures of religious practice. On the whole, these findings suggest that religious identity itself is more stigmatized in biology than in physics. Results have implications for how university professors—and academic scientists in particular—relate to the broader public.