Abstract: Somatization syndromes are highly prevalent disorders with unknown etiology and are challenging to treat. Integrating previous findings on alexithymia, attachment, and trauma, we hypothesized that somatization syndromes are associated with a specific internal representation of relationships—the unmet need for closeness with others (desire for interpersonal closeness combined with the fear of being rejected, hurt, or abandoned). Twenty patients with DSM-IV somatization syndromes and 20 well-matched healthy controls completed the Relationship Anecdotes Paradigm/Core Conflictual Relationship Themes interview and measures of interpersonal relatedness, alexithymia, and history of trauma. The results showed that the unmet need for closeness with others was the main internal representation of relationships in 90% of the patients and in only 10% of controls; it was also the strongest predictor of somatization syndrome diagnosis. This suggests that somatization syndromes are strongly associated with the interpersonal representation of the unmet need for closeness with others, which has direct implications for their treatment and future research on their etiology.