The present study is a 15-month follow-up of the effects of eye movement desensitization and reprocessing (EMDR) therapy on the functioning of 66 participants, 32 of whom were diagnosed with posttraumatic stress disorder (PTSD) prior to treatment. PTSD participants improved as much as those without the diagnosis, with both groups maintaining their gains at 15 months. At 15-month follow-up, the three 90-min sessions of EMDR previously administered (S. A. Wilson, L. A. Becker, & R. H. Tinker, 1995) produced an 84% reduction in PTSD diagnosis and a 68% reduction in PTSD symptoms. The average treatment effect size was 1.59; the average reliable change index was 3.37. Implications of the maintenance of EMDR treatment effects are discussed.