This study examined the lifetime prevalence of trauma exposure and posttraumatic stress disorder (PTSD) and their demographic, diagnostic, and trauma-related correlates in a clinical cohort of 426 patients with a first psychiatric admission for psychosis. The prevalence of trauma exposure was 68.5%. Female gender and substance abuse were risk factors for trauma exposure. The prevalence of PTSD was 14.3% in the full sample and 26.5% in those with trauma exposure. PTSD was less prevalent in patients with bipolar disorder and schizophrenia and was twice as common in women. Other significant risk factors were younger age and trauma exposure that was repeated and ongoing or that involved childhood victimization. The findings highlight the importance of systematically ascertaining trauma histories in patients with psychotic disorders.