This article focuses on some of the challenges of teaching science in a culture where science and religion sometimes appear to be or are set at odds with each other. Apparent conflicts between scholarly claims and religious claims are not limited to science, however--they occur in almost every subject. Many topics included in science education are acknowledged as controversial issues, for example, evolution, cloning, abortion and genetic engineering. These issues pose problems for science teachers, especially in a religiously based culture, because of the nature of the conflict between the implications of a scientific study of some of these issues and religion. Some other issues may not formally conflict with religion but teachers' views, or the way they interpret the religious view regarding these controversial issues, can create a false contradiction, which might influence their performance and, in turn, influence their students' learning. Therefore, there is a need to understand teachers' personal religious beliefs and practices around some of these, and the way their beliefs influence their performance in the classroom. This article describes a study conducted to address these needs. The study looks at the role and influence of religion on the science teacher's performance. The findings highlighted the powerful influence of teachers' religious beliefs in dealing with or gaining new knowledge (the epistemology and the ontology of science). Also, the findings found that teachers' religious beliefs are among the major constructs that drive teachers' ways of thinking and classroom practices about scientific issues related to religion. (Contains 3 tables, 1 figure, and 1 note.)