Background: People exposed to childhood trauma show insecure attachment patterns and are more prone to chronic and pain-related conditions, including migraine. The aim of this study was to explore the mediating role of attachment in the association between childhood trauma and adulthood chronic health conditions, with a focus on migraine. Methods: Respondents from a representative sample of citizens of the Czech Republic (n = 1800, mean age: 46.6 years, 48.7% male) were asked to report various chronic and pain-related conditions, childhood trauma (The Childhood Trauma Questionnaire, CTQ), and attachment anxiety and avoidance (The Experience in Close Relationships Revised, ECR-R) in a cross-sectional, questionnaire-based survey conducted in 2016. Structural equation models (SEM) adjusted for sociodemographic variables were used to assess the relationship between childhood trauma, adulthood attachment, and adulthood chronic health conditions (migraine, other pain-related conditions, chronic health conditions other than pain, no chronic health complaints). Results: After adjusting for sociodemographic variables, SEM confirmed a significant mediation of the relationship between childhood trauma and migraine through adulthood attachment. There was no mediation effect of adulthood attachment found in other health complaints. Conclusion: This study highlights the mediation effect of attachment in the link between childhood trauma and migraine. Attachment-based therapeutic interventions can be useful in the treatment of patients with migraine.