The purpose of the study was to explore the diagnostic reasoning process among nursing students with different learning environments. A case-study design was adopted. Twenty subjects were randomly drawn from the last year of a pre-registration nursing programme in two institutions, 10 from a university and 10 from a nursing school. They were asked to complete the Bigg's Study Process Questionnaire and identify the differential diagnosis for the three simulated scenarios. The results showed no significant difference in study approaches between the two groups. Two subjects from the university made an incorrect differential diagnosis, as did one from the nursing school. Subjects from the university showed a mix of horizontal (66.6%) and vertical reasoning patterns (33.4%), while those from the nursing school used horizontal (100%) reasoning patterns. The results indicated that all subjects from the nursing school adopted backward chaining strategies (horizontal) for decision-making, i.e. hypothesis-driven. About a third of the subjects from the university adopted forward chaining strategies (vertical), i.e. data-driven. The study did not show any particular advantages from either of the two learning environments in terms of study approach. However, it highlighted the variations in decision strategies among students in the university setting.