A survey of 100 patients referred to a specialist endodontic practice was undertaken to determine the frequency of various factors associated with continuing pain after endodontic treatment had been commenced by the patient's general dental practitioner. Information was obtained by questioning the patient, examining the tooth, reviewing information supplied by the referring dentist and by observation during subsequent treatment. There were 23 different factors associated with continuing pain--all patients had more than one factor; most (78 per cent) had four, five or six factors; the highest was 9 factors (2 per cent). The most commonly occurring factors were: lack of use of rubber dam (87 per cent), unsatisfactory temporary restorations (80 per cent), and inappropriate use of intracanal medicaments (71 per cent). The other factors were related to diagnostic or treatment errors that could have been avoided in most cases. This survey suggests that dentists need to pay more attention to basic treatment recommendations in order to predictably relieve pain when carrying out emergency endodontics.