The prognostic significance of the potential of cells to grow in tissue culture was studied in 50 patients with oesophageal cancer. The ability of cell lines to grow from resected oesophageal specimens was determined; from 50 patients, 21 cell lines were established (42 per cent). The patients were divided into two groups on this basis: group 1, from whom cancer cells could be grown as continuous cell lines and group 2, from whom cell lines could not be established. The cumulative survival rate of patients in group 1 was significantly lower than that of those in group 2 (P < 0.05). There was also a significantly higher incidence of lymph node metastases in group 1 (P < 0.05). These results suggest that the potential of cancer cells for growth is a useful long-term prognostic indicator for patients with oesophageal carcinoma.