This study aims to examine the relation between the degree of dissimilarity in patients' and relatives' perception of eating disorders (ED) and patient adjustment. Sixty ED patients and their relatives were interviewed. They completed the Spanish version for ED of the Revised Illness Perception Questionnaire (IPQ-R). Patients who agreed with their relatives that their illness was highly distressful, a chronic condition and with high identity, showed higher psychological distress than patients who did not agree with their relatives. When patients and relatives had fairly positive perceptions of illness controllability and curability, these patients showed lower levels of depression and anxiety.