Recent studies have suggested that the vulnerability to complicated grief (CG) may be rooted in insecure attachment styles developed in childhood. The aim of this study was to examine the etiologic relevance of childhood separation anxiety (CSA) to the onset of CG relative to major depressive disorder, posttraumatic stress disorder, and generalized anxiety disorder in bereaved individuals. The Structured Clinical Interview for the DSM-IV, Inventory of Complicated Grief-Revised, and CSA items from the Panic Agoraphobic Spectrum Questionnaire were administered to 283 recently bereaved community-dwelling residents at an average of 10.6 months postloss. CSA was significantly associated with CG (OR = 3.2; 95% CI, 1.2–8.9), adjusting for sex, level of education, kinship relationship to the deceased, prior history of psychiatric disorder, and history of childhood abuse. CSA was not significantly associated with major depressive disorder, posttraumatic stress disorder, or generalized anxiety disorder.