Trauma events are four times more prevalent in inmates than in the general public and are associated with increased recidivism and other mental and physical health issues.To evaluate the effects of Transcendental Meditation (TM) on trauma symptoms in male inmates.One hundred eighty-one inmates with a moderate- to high-risk criminal profile were randomly assigned to either the TM program or to a usual care control group.The Trauma Symptom Checklist and the Perceived Stress Scale were administered at baseline and four-month posttest.Significant reductions in total trauma symptoms, anxiety, depression, dissociation, and sleep disturbance subscales, and perceived stress in the TM group were found compared with controls (all p values < 0.001). The high-trauma subgroup analysis further showed a higher magnitude of effects in the TM group compared with controls on all outcomes, with Cohen effect sizes ranging from 0.67 to 0.89.Results are consistent with those of prior studies of the TM program in other populations and its effects on trauma symptoms and perceived stress.