Research shows that a surface approach to learning is more common among students in the natural sciences, while students representing the "soft" sciences are more likely to apply a deep approach. However, findings conflict concerning the stability of approaches to learning in general. This study explores the variation in students' approaches to learning and aims to analyse factors that are particularly related to the deep approach. The participants were first-year pharmacy students who completed a questionnaire at the beginning and end of the course. The students were interviewed to determine factors related to changes in their deep approach. The results revealed significant changes in approaches to learning at the group level. Yet, closer analysis showed much more variation at the individual level. Findings based on the interviews indicated different factors, self-regulation skills among them, which seemed to explain both the changes in and stability of the students' deep approach.