In this study reader performance in resting electrocardiographic (ECG) reading and case summary interpretation was investigated. Eight cardiologists were asked to read independently 105 paired ECG--Case summary sheets on either two or four occasions. The order of ECG--Case summary inspection for each sheet was randomized over trials. The results show low levels of inter- and intra-reader reliability when physicians report on ECG traces. Reference to coronary arteriographic information confirms that the resting ECG has limited utility in the detection of coronary artery disease.