A modified needle for external ventricular drainage is presented. Contrary to conventional spinal needles with this instrument the sharp guide can be withdrawn after penetration of the dura, thus, no sharp instrument affects the brain, nor remains within the ventricles in cases of continuous drainage. Furthermore, depth of penetration can be determined preoperatively by means of a set screw also facilitating fixation of the needle. To date, we have used this modified needle in 50 patients for short or long term CSF drainage and for CSF pressure measurements. Trephination was performed with a hand or battery-driven drill. Except for an infection in one case we found no serious complications in our patients. In our opinion, ventricle puncture for external drainage and pressure measurement with this device is a simple and safe method and can be performed on the ward under local anaesthesia.