Multi-channel magnetocardiography (MCG) has been proposed to detect ischemic heart disease because its sensitivity is quite high comparing with other conventional diagnostic tools. Especially, current map and magnetic field map of MCG provide crucial information on whether myocardiac muscles maintain the normal conduction pathway. In addition, MCG parameters derived from repolarization are useful to detect coronary artery disease. Recently, there was a study reporting that R- and T- wave amplitude are highly correlated with ischemic heart disease. In this study, we studied R- and T-wave amplitude and their ratio as well as MCG parameters. MCG data from 20 young, 20 age-matched controls, and 20 myocardial infarction (MI) patients were analyzed. As a result, MCG parameters showed significant change in MI patients comparing to those of controls. R- and T-wave amplitude of MI patients showed a feature of severe ischemic heart disease even though it was difficult to find consistent values. Further study is needed to reveal the relations between small T-wave amplitude and coronary artery disease.