In research literature, two study orientations have been identified: meaning orientation and reproducing orientation. Few studies have examined how study orientations and conceptions of knowledge (epistemologies) interrelate. Further, longitudinal studies of the development of orientations and of conceptions of knowledge in relation to academic achievement are scarce. The study set out:(i) to examine the relationship between study orientations and conceptions of knowledge; (ii) to investigate how these kinds of beliefs change during short, career aimed studies of natural science; (iii) to explore how study orientations and changes in them are related to study success. The sample consisted of 66 undergraduate students of pharmacy studying at a Finnish university. Participants filled in a questionnaire regarding study orientations and conceptions of knowledge at the beginning of their studies and after 3 years of study. Results showed a relationship between reproducing orientation and dualist conceptions of knowledge. Reproducing orientation and dualism diminished during undergraduate natural science studies. Further, students' reproducing orientation after the last study year was negatively related to their study success. In addition, a favourable development was detected in the group of above-average achievers, who maintained their initial level of meaning orientation while diminishing their level of reproducing orientation. Implications for instruction are discussed.