Resection was performed in 85 patients with ampullary and in 150 with ductal pancreatic head carcinoma. Curative resection was achieved in 98 and 87 per cent respectively. Patient survival at 5 years after exclusion of hospital deaths was 38 versus 16 per cent respectively. The patients were compared retrospectively in a multivariate survival analysis. For patients with pancreatic carcinoma, residual tumour stage, tumour size and grading were independent prognostic factors, but for those with ampullary carcinoma only tumour size was a prognostic factor. Lymph node metastasis impaired prognosis, but this effect was demonstrable for both groups only after univariate analysis. The Union Internacional Contra la Cancrum classification system was not a reliable parameter of prognosis after resection of ampullary carcinoma. Patients with ampullary cancer appear to have a better prognosis intrinsically than those with pancreatic head tumours, and not simply because they present at an earlier stage. The difference in prognosis cannot be explained sufficiently by a differential importance of the various survival variables.