This paper is a report of a study to explore, from the perspective of nursing students, how they acquire clinical decision-making skills and how well-prepared they feel in this respect regarding their responsibilities as Registered Nurses. Previous research has focused mainly on exploring experienced nurses' judgement and decision-making. Some studies have elicited senior nursing students' understanding of the process, but none has explored the development of clinical decision-making skills throughout the educational programme and in the first year as a Registered Nurse. A volunteer sample of 20 respondents, broadly representative of the student cohort regarding qualifications, age, gender and nursing specialty, was recruited. A longitudinal hermeneutic phenomenological study was carried out from 2000 to 2004, using interviews, reflective journals, care studies, critical incident analyses and document analysis. Ten conceptions of nursing and 10 perceptions of clinical decision-making were identified and a growing pattern of inter-relationships between them became apparent. A 'matrix model' was developed by cross-referencing the two thematic categories within the timeline of respondents' developmental journey through significant milestones and changing contexts. As Registered Nurses they found having to 'think on your feet' without the 'comfort blanket' of student status both a stressful and formative learning experience. Further collaboration between education and health service partners is recommended to integrate clinical decision-making throughout the nursing curriculum, enhance the development of such vital skills, and facilitate the transition from student to Registered Nurse.