SPECT with the benzodiazepine receptor antagonist I-123-Iomazenil was performed in 33 patients with intractable partial seizures for pre-operative evaluation. The results combined with MRI and 99mTc-HMPAO-SPECT findings were com-pared with the video-assisted EEG monitoring (''gold standard'') which localised the focus in 25 patients. 11 patients underwent surgical resection of the epileptogenic area and became seizure-free for a period up to 13 months. The Iomazenil SPECT had a significantly higher sensitivity compared to 99mTc-HMPAO in the visualization of an epileptogenic area and should be regularly used in the diagnostic of medically intractable partial seizures.