This paper discusses major themes presented in the published literature concerning clinical decision making and links these to the practice of emergency department nurse triage. Themes discussed include: approaches to decision research in nursing and medicine; decision autonomy in nursing practice and clinical decision making under conditions of uncertainty. Some assumptions underpinning clinical decision-making frameworks are explored and the use of triage scales, algorithms and intuitive thought processes are discussed in terms of clinical practice. In addition, the strengths and limitations of each approach are outlined. It is argued that naturalistic research methods are necessary in order to describe the often uncertain and frequently chaotic environment in which triage decisions are made. This research must occur in order to evaluate and improve both the triage process and the outcomes of these decisions in practice.