The risk of presenting with advanced stage vs. early stage disease was evaluated in a prospective study of 336 consecutive patients with oral and oropharyngeal carcinomas referred to three head and neck surgery services in Sao Paulo, Curitiba and Goiania during the period from February 1986 to December 1988. Income and educational levels were not associated with stage distribution. The risk of having advanced disease was dependent upon male gender. Another important determinant of advanced stage was tumour location on the less visible surfaces of the oral cavity and oropharynx. Although there was a clear increase in delay of referral among cases who were seen by more than one health professional, duration of symptoms and patient and professional delays were not associated with the risk of advanced disease in unifactorial analysis. The following factors were independently associated with the risk of advanced disease for lip carcinoma: a painful ulcer, alcoholism and delay caused by a non-specialist medical doctor. The risk factors associated to advanced oral carcinoma were: type of lesion, odynophagia/dysphagia, delay caused by a dentist and delay caused by a non-specialist medical doctor. Two of the most important immediate consequences of advanced stage were a conspicuous increase in treatment costs and a longer hospital stay.