Employing the apparatus which we made of analog computers, spatial velocity electrocardiograms were taken from 321 cases composed of 54 normal cases, 71 cases of left ventricular hypertrophy, 12 cases of right ventricular hypertrophy, 14 cases of complete left bundle branch block, 30 cases of complete right bundle branch block, 10 cases of incomplete right bundle branch block, 41 cases of myocardial infarction and 89 cases of ventricular premature beats. The normal sVECG was composed of 8 chief deflections: π1 and π2 as the counterpart of the P wave of the electrocardiogram, ξ, ρ1, ρ2 and σ as that of the QRS, and τ1 and τ2 as that of the T wave. Normally ρ2 and τ2 were larger than ρ1 and τ1, respectively. In ventricular hypertrophy ξ ρ σ tended to show more splitting and τ to be flatter or the ratio τ1/τ2 was smaller than normal. In left bundle branch block splitting of ξ Ρ σ was most marked and in right bundle branch block σ was wide, frequently making a separate σ'. In myocardial infarction ξ was wide occasionally, and σ was usually wide. ρ1 was often larger than ρ2 in anterior myocardial infarction and was smaller than ρ2 in pos-terior myocardial infarction. τ was variously abnormal in most cases. These and other findings were found useful for diagnosis and the sVECG was found to be especially useful when combined with the vectorcardiogram by effectively supplementing its weak points.