The incidence of regional lymph node metastasis in early Barrett's carcinoma is determined by the depth of infiltration of the tumour. The present study investigated the possible relationship between the depth of infiltration of the tumour, its degree of differentiation and the incidence of lymphatic vessel and venous invasion in early Barrett's carcinoma. To this end, a total of 805 endoscopically resected specimens obtained from 472 patients with early Barrett's carcinomas were analysed. The results of this analysis revealed that increasing depth of tumour infiltration is associated with an increase in the incidence of poorly differentiated carcinomas--from 0.8% for lesions limited to the mucosa (m1) to 41.4% when the depth of infiltration extended to the lower third of the submucosa (sm3). A similar correlation was also found for the incidence of lymphatic vessel invasion (m1, 0.6%; sm3, 44.8%) and for venous invasion (m1, 0%; sm3, 13.8%). All of these observations proved to be statistically highly significant (p < 0.001). In conclusion, the results show that the degree of differentiation, as well as the incidence of lymphatic vessel and venous invasion, correlates with the depth of infiltration of the early carcinoma in Barrett's oesophagus.