The authors performed pelvic and lumbo-aortic tomodensitometry (TDM) in 67 patients with invasive carcinoma of the cervix. Localisation of the cervix is aided by the insertion of a vaginal marker and by opacification of the bladder and rectum. The density and appearance of tumour tissue are identical to those of normal uterine muscle. Under such conditions, TDM is of no use in seeing partial or total involvement of the cervix without any increase in cervical size. TDM gives a clear picture of hypertrophic neoplastic cervices and may be used to obtain exact measurements. TDM offers valuable information in cases of spread to the parametrium, lymphadenopathy or visceral metastases. During radium therapy, TDM shows the relationships between the radioactive sources and the centri-pelvic tumour. It facilitates the drawing of isodose curves. TDM is not a method suitable for the early diagnosis of carcinoma of the cervix. It adds very useful complementary information to clinical examination and classical investigation.