During the last seven years (1985-91) 28 primary tumours in the cauda among 104 intraspinal tumors were observed. The largest group (71%) comprised ependymomas and neurinomas. The rest included 5 lipomas, 2 astrocytomas and 1 epidermoid. Low-back pain without or with sciatic or crural irradiation was the most common initial symptom. The length of symptomatology is generally measured in months, because pain is erroneously referred to discal pathology for long time. The X-ray standard test and the CT scan have been of modest utility in the diagnosis of these lesions, but however they have been necessary for diagnostic screening. The MNR, a bloodness test, showed an important diagnostic value for the identification of these tumors; it is also useful in follow-up to exclude recurrence. The lipoma's and ependymoma's surgery, although performed by microsurgical techniques, showed great problems. Total removal of the ependymomas assured no recurrence at the follow-up. Sphincter disturbances were frequent after the operation, but they disappeared after some months. In most patients with lipomas the resection was partial, but at follow-up they were symptomless. Neurinomas' surgery presented less technical difficulties and the postoperative course was more favorable. Astrocytomas underwent to radiotherapy but their prognosis is not favorable.