Identification of biomarkers of vulnerability for Major Depressive Disorder is a high priority, but heterogeneity of the diagnosis can hinder research. Biomarkers of vulnerability should also be present in the absence of the diagnosis. The present study examined the magnitude of the error-related negativity (ERN), an event-related potential component following errors in a sample with remitted melancholic depression (N = 17), remitted non-melancholic depression (N = 33), and healthy controls (N = 55). Remitted melancholic depression was uniquely characterized by a blunted ERN relative to the other two groups. Individuals with remitted non-melancholic depression did not differ from controls in the magnitude of the ERN. This was the case despite the fact that the melancholic and non-melancholic groups did not differ in course or severity of their past illnesses, or in their current functioning. Results suggest that the blunted ERN may be a viable vulnerability marker for melancholia.