To assess the feasibility of measuring changes in gene expression associated with post-traumatic stress disorder (PTSD) treatment using emotional freedom techniques (EFT). Participants were randomized into an EFT group receiving EFT and treatment as usual (TAU) throughout a 10-week intervention period and a group receiving only TAU during the intervention period and then receiving EFT. A community clinic and a research institute in California. Sixteen veterans with clinical levels of PTSD symptoms. Ten hour-long sessions of EFT. Messenger RNA levels for a focused panel of 93 genes related to PTSD. The Symptom Assessment 45 questionnaire, Hospital Anxiety and Depression Scale, Insomnia Severity Scale, SF-12v2 for physical impairments, and Rivermead Postconcussion Symptoms Questionnaire. Pre-, posttreatment, and follow-up mean scores on questionnaires were assessed using repeated measures 1-way analysis of variance. A Student t test and post hoc analyses were performed on gene expression data. Post-traumatic stress disorder symptoms declined significantly in the EFT group (-53%, P < .0001). Participants maintained their gains on follow-up. Significant differential expression of 6 genes was found ( P < .05) when comparing the expression levels before and after the intervention period in participants receiving EFT. Study results identify candidate gene expression correlates of successful PTSD treatment, providing guidelines for the design of further studies aimed at exploring the epigenetic effects of EFT.