Background and Objectives. Significant numbers of patients refer themselves to A&E departments for conditions which are neither accidents nor emergencies, relatively few of which require specific hospital treatment. These patients and their conditions have been described as 'inappropriate'. The objective of this paper is to review research relating to the definition, incidence and reasons for attendance of 'inappropriate' attenders. There is no accepted practical definition of what constitutes an 'appropriate' attender to an A&E department nor of what constitutes an 'emergency'. It is therefore not surprising that there is enormous variability (from 6 to 80%) regarding the proportion of visits judged to be inappropriate. All definitions rely completely on implicit and subjective judgements to determine appropriateness. The decision making of patients in opting to attend accident and emergency departments in preference to consulting their GP is complex, involving an interplay of social, psychological and medical factors.Conclusions. An analysis of reported work suggests that the most important factors are the perceived appropriateness of the condition for A&E, A&E accessibility and GP availability. A major deficiency in the available research is that patients have been retrospectively labelled as 'inappropriate' by medical personnel on the basis of the results of patient assessment and treatment. This review suggests that definitions and putative management strategies must consider the social and psychological context of the patients' decisions to attend.