Endoscopy has been the primary diagnostic test in the investigation of patients with suspected gastric malignancy. Among patients undergoing endoscopy of the stomach the number of elderly people has been increasing and cardio-vascular complications have been reported more frequently. This is the report of a study to determine cardiodynamic effects of endoscopy in patients with cardiovascular disor-ders. Changes in the heart rate, blood pressure, ECG, occur-ing at the time of endoscopy of the stomach were studied in a group of 59 cases of cardiovascular disease and in a control group of 27 cases. With regard to arrhythmias appearing at the time of endoscopy of the stomach, ventricular and atrial premature beats were the most numerous. Atrial fibrillation, as well as ventricular bigeminy were encountered. Two cases of atrial fibrillation continued even after the end of the examination. STT changes during endoscopy were found most freq-uently in the ischemic heart disease group and in the valvular heart disease group. There were 3 cases in which severe ST depression made it necessary to stop the exam-ination. The cardiovascular changes generally occured at the begining of the endoscopy examination. Two mg of pro-pranolol IV. seemed to be effective in preventing chang-es of heart rate. The data clearly permit the conclusion that upper G I endoscopy may be frequently comlicated by cardiovascular aberration. With sufficient care and some precautionary measures, however, these complications appear not to be of serious nature.