OBJECTIVES To identify the key features of effective clinical supervision in the emergency department (ED) from the perspectives of enthusiastic consultants and specialist registrars. To highlight the importance of clinical supervision within emergency medicine, and identify obstructions to its occurrence in everyday practice. METHODS A critical incident study was undertaken consisting of structured interviews, conducted by telephone or in person, with 18 consultants and higher level trainees selected for their interest in supervision. RESULTS Direct clinical supervision of key practical skills and patient management steps was considered to be of paramount importance in providing quality patient care and significantly enhancing professional confidence. The adequacy of supervision varied depending upon patient presentation. Trainees were concerned with the competence and skills of their supervisor; consultants were concerned with wider systemic constraints upon the provision of adequate supervision to juniors. CONCLUSIONS The value of supervision extends to all patient presentations in the ED. The study raised questions concerning the appropriate attitudes and qualifications for supervisors. Protected supervisory time for those with trainees is mandatory, and must be incorporated within ED consultant job planning.