If the goals of science education reform are to be realized, science instruction must change across the academic spectrum, including at the collegiate level. This study examines the beliefs and teaching practices of three scientists as they designed and implemented an integrated science course for nonmajors that was designed to emphasize the nature of science. Our results indicated that, like public school teachers, scientists' beliefs about the nature of science are manifested in their enactment of curriculum--although this manifestation is clearly not a straightforward or simplistic one. Personal beliefs about the nature of science can differ from those of the course, thus resulting in an enactment that differs from original conceptions. Even when personal beliefs match those of the course, sophisticated understandings of the nature of science are not enough to ensure the straightforward translation of beliefs into practice. Mitigating factors included limited pedagogical content knowledge, difficulty in achieving integration of the scientific disciplines, and lack of opportunity and scaffolding to forge true consensus between the participating scientists.