Abstract The equivalent heart dipole and quadrupole were determined on a normal male subject for two origins in the heart region. Determinations were based on a detailed measurement of the torso surface geometry, a digital computer solution of transfer impedances relating unit dipole and quadrupole components to surface potentials they generate, and the measurement of 284 ECG's. Addition of the quadrupole contribution gave a better fit to the surface ECG. The RMS error during QRS was 0.091 mv. for dipole alone and 0.054 mv. for dipole plus quadrupole representing respectively 23 per cent and 14 per cent of the total RMS value of the recorded ECG's. Similar values for P were 0.024 mv. (46 per cent) for dipole and 0.015 mv. (29 per cent) for dipole plus quadrupole. For T the results were 0.058 mv. (22 per cent) and 0.048 mv. (18 per cent).