Sixty-four ballistocardiograms were obtained on a portable equalized electromagnetic ballistocardiograph from 18 young adult males with acute rheumatic fever. Thirteen of these subjects had clinical findings suggestive of heart involvement and five did not. Abnormal records were obtained from only one patient in each group. It appears, therefore, that abnormal ballistocardiograms are not often found in acute rheumatic fever even when evidences of cardiac involvement are present.