The records of 123 patients who had previously be operated upon for intra-cranial tumors are studied to find symptoms of recurrency. 82 of these patients underwent a second operation. The value of CT Scan, cinegammagraphy and angiography are compared. CT Scan yields the best results to detect recurrency and its place. Using both CT Scan and cinegammagraphy increases reliability for difficult cases, mainly in the cases of multiple lesions. Angiography is no longer used to detect recurrencies but only just before operation.