Forty-three patients with nasopharyngeal carcinoma are classified by the four staging systems in common clinical use. There is no statistically significant difference in predicting prognosis when the corresponding stages in each system are compared. A number of factors may be responsible. It may be due to the clinician's inability to assess accurately certain points used for staging or there may be other factors not included in the criteria for staging which affect prognosis, such as the degree of tumour differentiation and viral serological values.