Objective: The aim of the current study is to characterize the relationship between posttraumatic stress disorder (PTSD) and alcohol dependence (AD) in women, distinguishing PTSD-specific infl uences on AD from the contribution of co-occurring psychiatric conditions and from the infl uences of trauma more generally. Method Trauma histories and DSM-IV lifetime diagnoses, including PTSD and AD, were obtained via telephone interview from 3,768 female twins.Based on PTSD status and trauma history, participants were categorized as no trauma (43.7%), trauma without PTSD (52.6%), or trauma with PTSD (3.7%). Cox proportional hazards regression analyses were conducted using trauma/PTSD status to predict AD, first adjusting only for ethnicity and parental problem drinking, then including conduct disorder, major depressive disorder, regular smoking, and cannabis abuse. Results: Before accounting for psychiatric covariates, elevated rates of AD were evident in both trauma-exposed groups, but those with PTSD were at signifi cantly greater risk for AD than those without PTSD.This distinction was no longer statistically signifi cant when psychiatric covariates were included in the model, but both trauma-exposed groups continued to show elevated odds of developing AD compared with the no trauma group. Conclusions: The elevated rates of AD in women who have experienced trauma are not accounted for in full by psychiatric conditions that commonly co-occur with AD and trauma exposure. The greater likelihood of developing AD in the subset of trauma-exposed individuals who develop PTSD may refl ect higher levels of distress and/ or higher rates of psychopathology associated with traumas that lead to PTSD rather than PTSD-specifi c infl uences.