Human personality has brain correlates that exert manifold influences on biological processes. This study investigates relations between emotional personality and heart activity. Our data demonstrate that emotional personality is related to a specific cardiac amplitude signature in the resting electrocardiogram (ECG). Two experiments using functional magnetic resonance imaging show that this signature correlates with brain activity in the amygdala and the hippocampus during the processing of musical stimuli with emotional valence. Additionally, this cardiac signature correlates with subjective indices of emotionality (as measured by the Revised Toronto Alexithymia Scale), and with both time and frequency domain measures of the heart rate variability. The results demonstrate intricate connections between emotional personality and the heart by showing that ECG amplitude patterns provide considerably more information about an individual's emotionality than previously believed. The finding of a cardiac signature of emotional personality opens new perspectives for the investigation of relations between emotional dysbalance and cardiovascular disease.