A series of studies were conducted to investigate students' metacognitive development in a second year chemical engineering course. The first of these was an exploratory study involving observation together with some limited interviewing. This was followed by a major study with two phases, the first of which involved a series of individual interviews with eleven students over the duration of the course, and the second of which involved a follow-up interview with each student two years later. In the first phase of the major study a theoretical framework characterising metacognitive development as a shift in approach to learning was utilised. The present paper draws on the findings of the second phase of the major study to both confirm the validity of this framework and also point to some of its shortcomings, specifically regarding the necessity of a certain emotional state in order for metacognitive development to take place, and the importance of the formation of a professional identity. It is suggested that metacognitive development needs to be characterised in broader terms than the usual cognitive focus in order to more fully account for students' experiences of learning.