This retrospective study of 56 patients with carcinoma of the uterine cervix treated with radical radiotherapy at the Royal Marsden Hospital, London, examined whether simple measurements of maximum tumour dimension from computerized axial tomographic (CT) scans have any prognostic significance. Our results indicate that tumour depth (i.e. maximum antero-posterior dimension) of 4 cm or more is associated with a statistically significant increased relative risk of death of 2.4 (95% CI 1.1-5.5; p = 0.045), as compared with tumours with a depth of less than 4 cm. In addition, there was a clear correlation between tumour depth and lymph node involvement (r = 0.36; p < 0.01), and tumour depth and width (r = 0.70; p < 0.005). We suggest that a measurement of maximum tumour depth from the staging CT scan in these patients provides valuable additional information about likely occult lymph node metastases and prognosis, over and above that suggested by the FIGO staging system alone.