Stereotactic endoscopic techniques are extremely helpful in diagnosis and therapy of cystic intracerebral space occupying lesions. Acute space occupying lesions can be managed effectively and without major tissue traumatization. Up to now we have operated on more than 70 cystic intracerebral space occupying lesions with a stereotactic endoscopic technique. The main diagnoses were colloid cysts, cystic craniopharyngeoma, arachnoidal and pineal cysts. In must be stressed that in cystic anaplastic astrocytomas and glioblastomas as well as metastases only an acute inner cerebral decompression can be achieved by neuroendoscopic techniques in combination with the application of reservoir systems. In benign parenchymal or intraventricular cysts neuroendoscopic intervention is performed for definitive treatment. The results are overall encouraging. There was no operative mortality and operative morbidity was below 3%. Postoperative follow-up in patients with benign cysts showed no evidence of recurrence.