Aims/objectives/background Post-traumatic stress disorder (PTSD) is a leading cause of morbidity among military veterans, with up to one-in-five individuals with PTSD also having psychotic symptoms. The current study was designed to determine the association between a known family history of psychiatric illness and risk of developing psychosis in patients with PTSD. Methods Retrospective medical record review was performed on a cohort study of 414 consecutive individuals admitted to the Veteran Administration in 2014 with a diagnosis of military-related PTSD, but without a prior diagnosis of a psychotic disorder. PTSD with psychotic features was defined as the presence of hallucinations, paranoia, other delusions, thought insertion, withdrawal, broadcasting, and/or dissociative episodes. Results Overall, 22.9% of individuals with PTSD had psychotic symptoms. Having a first-degree relative with bipolar affective and with anxiety disorders was associated with an increased risk of PTSD with psychosis (odds ratio=2.01, 95% confidence interval: 1.01-4.45 and odds ratio=2.72, 95% confidence interval: 1.16-6.41, respectively). A family history of schizophrenia or depression was not associated with risk of developing psychotic features in patients with PTSD. In veterans with military-related PTSD, a familial vulnerability for bipolar disorder and anxiety disorders was associated with an increased risk of developing PTSD with psychotic features. These are preliminary data, given the limitations of a retrospective record review design. These results await replication in future prospective direct family interview studies.