Necropsy specimens of the oesophagus from 110 South African Blacks and from a control group of 110 Whites were examined for dysplasia and associated lesions of the epithelium, using the 'Swiss roll' technique. In 4 Black males (3,3%) focal areas of moderate to severe dysplasia were found. This means that the incidence of dysplasia is far higher than that of carcinoma, which seems to indicate that dysplasia is probably a reversible lesion. Parabasal cell hyperplasia was found in 44,5% of Blacks and in 29% of Whites. Keratohyaline granules in superficial epithelium also occurred more frequently in Blacks (49%) than in Whites (29%). These two conditions might be the result of chronic irritation and would probably not be significant markers in a screening programme for carcinoma. However, the presence of exfoliative dysplastic cells almost certainly indicates premalignant change in the epithelium.