The relationship between p53 point mutation and patient survival was examined in 328 colorectal cancer patients. Point mutation was detected in 51% (166/328) of cases and was associated with a poorer prognosis in univariate and multivariate analysis. However, subcohort analysis showed that this relationship was restricted to patients with lymphatic dissemination, patients without evident distant metastatic lesions at the time of presentation and in tumours confined to the distal colorectum. These results suggest that the utility of p53 point mutation as a specific, patient based prognostic marker may be restricted to certain classes of patients.