Non-ionic contrast medium, iopromide(Ultravist), was compared with ionic contrast medium, ioxitalamate(Telebrix), for efficacy and safety in 63 patients undergoing left ventriculography, In all patients, adverse symptoms and signs including pain, heat sense, nausea, vomiting, etc., were checked during and shortly after the injection. Blood pressure, heart rate, EKG and left ventricular pressure were also monitored during the study, andCBC, UA, BUN and creatinine were checked before and 24 hours after the study, The cineangiographic films were analysed and compared by 2 radiologists for the quality. Serious adverse effect did not occur in any case. Minor effects, especially nausea, were less frequently caused by non-ionic contrast medium than by ionic contrast medium, and heat sense to non-ionic contrast medium was less severe than to ionic contrast medium. Except slightly elevated LVEDP at 1,5 minutes after the study in patients given ionic contrast medium, there was no significantchange of electrophysiologic parameters and laboratory findings in both groups. In regard to image quality, therewas no significant difference between ionic and non-ionic contrast medium. Thus non-ionic contrast medium, iopromide, appears to be safer for use in left ventriculography than the conventional ionic contrast medium, particularly in those patients at high risk of adverse effects.