BACKGROUND:In the first population-based study of psychopathology conducted in Haiti, we documented earthquake-related experiences associated with risk for posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) 2-4 months following the 2010 Haiti earthquake. METHODS:A population-based survey was conducted of 1,323 survivors randomly selected from the general nondisplaced community, internally displaced persons camps, and a community clinic. Respondents were from the Nazon area of Port-au-Prince, ∼20 miles from the epicenter. RESULTS:Respondents (90.5%) reported at least one relative/close friend injured/killed, 93% saw dead bodies, and 20.9% lost their job post-earthquake. The prevalence of PTSD (24.6%) and MDD (28.3%) was high. History of violent trauma was associated with risk of PTSD and MDD (adjusted odds ratio [AOR] 1.4, 95% confidence interval [CI], 1.0-1.9; AOR, 1.7, 95% CI 1.3, 2.2, respectively). Low social support (AOR, 1.7, 95% CI 1.2, 2.3; AOR 1.4, 95% CI 1.0, 1.9, respectively) increased risk of PTSD and MDD among women. Suffering damage to the home increased risk of MDD in males (AOR 2.8, 95% CI 1.5, 5.5). Associations between being trapped in rubble, major damage to house, job loss, and PTSD; and participation in rescue/recovery, friends/family injured/killed, and MDD varied based on prior history of violent trauma. CONCLUSIONS:Addressing mental health in a post-earthquake setting such as Haiti will require focusing resources on screening and treatment of identified vulnerable groups while targeting improvement of post-earthquake living conditions. Investment in sources of social support for women may make help mitigate the vulnerability of women to PTSD and MDD.