The present study investigated whether magnetocardiograms (MCGs) could noninvasively detect the His potential. In 22 patients, the His - ventricular (HV) intervals in MCGs (64-channel system, 2-min signal averaging, filter: 0.1-100 Hz, and band-eliminating filter of 50 Hz) were compared with those recorded in an electrophysiologic study (EPS, filter: 30-400 Hz). In 14 of the patients (64 %), the His potential was recorded in the MCGs. There was a correlation between the HV intervals in the MCGs and those in the EPS (R = 0.81, p<0.01). This study indicates that MCGs can be used to investigate the specialized conduction systems for which EPS is currently used.