ObjectiveThe mechanisms underlying the association between adult attachment and health are not well understood. In the current study, we investigated the relationship between attachment anxiety, attachment avoidance, inflammation, and length of hospital stay in coronary artery bypass graft (CABG) surgery patients.Method167 CABG patients completed an attachment questionnaire prior to surgery, and blood samples were taken before and after surgery to assess inflammatory activity.ResultsWe found that attachment anxiety predicted higher plasma interleukin 6 (IL-6) concentration, and this association was mediated by self-reported sleep quality. Anxious attachment also predicted longer hospital stays following CABG surgery, even after controlling for demographic and clinical factors.ConclusionThese data suggest that increased levels of IL-6 may be a process linking adult attachment anxiety with health outcomes.