This is a retrospective analysis of 4768 patients with undifferentiated or non-keratinising carcinoma of the nasopharynx who were treated during 1 January 1976 to 31 December 1985. The mean duration of symptoms before diagnosis was 8 months (range, 1-36 months for 95% of patients). A significant association between the duration of symptoms and the presenting stage was observed (P<0.001); 58% and 39% of stage I and stage V patients, respectively, reported as having had symptoms for less than 6 months. Of the later presenters (those having had symptoms for 6 months or longer), 89% were given a full course of radical megavoltage radiotherapy, but 6% were too advanced for any irradiation attempt. Consequently, the 10-year actuarial disease-specific survival was significantly higher among the early presenters: 48% versus 42% (P<0.001). The importance of early detection is emphasised.