Twenty-nine cases were examined by eeg before and after angiocardiography. In 20 the contrast medium was injected into the ascending aorta and in the remainder, the injection was made into the pulmonary artery or right ventricle. Slowing of the activity was observed in 6 cases, with return to a normal record within 2 to 14 days after the injection. In another 3, a reduction of paroxysmal activity was seen, and in 20 cases the eeg was completely unchanged. The influences of the anesthesia are discussed.