This article describes views about the nature of science held by a small sample of science students in their final year at the university. In a longitudinal interview study, 11 students were asked questions about the nature of science during the time they were involved in project work. Statements about the nature of science were characterized and coded using a framework drawing on aspects of the epistemology and sociology of science. The framework in this study has three distinct areas: the relationship between data and knowledge claims, the nature of lines of scientific enquiry, and science as a social activity. The students in our sample tended to see knowledge claims as resting solely on empirical grounds, although some students mentioned social factors as also being important. Many of the students showed significant development in their understanding of how lines of scientific enquiry are influenced by theoretical developments within a discipline, over the 5–8 month period of their project work. Issues relating to scientists working as a community were underrepresented in the students' discussions about science. Individual students drew upon a range of views about the nature of science, depending on the scientific context being discussed. © 1999 John Wiley & Sons, Inc. J Res Sci Teach 36: 201–219, 1999