Background In spite of an elevated prevalence of trauma histories among prisoners, there has been little research examining the relationship between incarceration and posttraumatic stress disorder (PTSD); this is especially true for Black Americans. Aims To examine relationships between PTSD and incarceration in a nationally representative sample of Black Americans. Methods We conducted analysis of data from the National Survey of American Life sample of 5008 Black American adults in the USA. Multivariate logistic regression analyses controlling for demographic factors including age, gender, home region and education were conducted to examine whether incarceration status was independently associated with PTSD. Results Incarceration was significantly associated with trauma exposure, PTSD in the 12 months prior to interview and lifetime PTSD, even while controlling for demographic covariates. Conclusions and implications for practice Incarceration, trauma exposure and PTSD share a significant number of risk factors and co‐vary frequently in some populations, including the one of Black Americans investigated in this study. Interventions that can reduce shared risk factors for incarceration and PTSD and/or facilitate successful treatment of the established condition have the potential to make a large positive impact among incarcerated and formerly incarcerated people. Copyright © 2015 John Wiley & Sons, Ltd.