Two types of EEG abnormalities were recorded after myelography, cisternography and ventriculography with metrizamide (Amipaque) in 292 patients. One, probably without clinical significance, occurred in the EEG of 36 patients as theta waves the following day. The other was of a more serious nature and was recorded as paroxysms of delta waves or spikes in the EEG of 11 patients minutes or some few hours after the myelography. One of these patients developed epileptic seizures.