This paper reports the findings of a study designed to assess 16 experienced geography teachers' epistemological beliefs about learning and teaching and their awareness of common alternative conceptions held by students. The investigation forms part of a larger study exploring the ways in which experienced geography teachers use their knowledge of students' ideas to inform instruction. The results suggest that teachers' knowledge of students' ideas and epistemological beliefs about learning and teaching are both complex and varied. Teachers with an understanding of the constructed and robust nature of students' ideas, however, are more likely to hold a nuanced, detailed and accurate knowledge of students' common alternative conceptions. The implications of these findings for professional practice are discussed together with suggestions for future research.