This study used a quantitative, single-case study design to examine the effectiveness of the integration of intensive eye movement desensitization and reprocessing (EMDR) and ego state therapy for the treatment of an individual diagnosed with comorbid posttraumatic stress disorder (PTSD), major depressive disorder (MDD), and generalized anxiety disorder (GAD). The participant received 25.5 hr of treatment in a 3-week period, followed with 12 hr of primarily supportive therapy over the next 6-week period. Clinical symptoms decreased as evidenced by reduction in scores from baseline to 6-week follow-up on the following scales: Beck Depression Inventory (BDI) from 46 (severe depression) to 15 (mild mood disorder), Beck Anxiety Inventory (BAI) from 37 (severe anxiety) to 25 (moderate anxiety), and Impact of Events Scale from 50 (severe PTSD symptoms) to 12 (below PTSD cutoff ). Scores showed further reductions at 6-month follow-up. Results show the apparent effectiveness of the integration of intensive EMDR and ego state work.