ABSTRACT Background: It is unknown whether remotely delivered intensive trauma-focused therapy not only is an effective treatment for PTSD, but also for Complex PTSD. Objective: Testing the hypothesis that a brief, fully remotely administered intensive trauma-focused treatment programme for individuals with PTSD and Complex PTSD would be safe, and associated with a significant decline of the corresponding symptoms and diagnostic status. Method: The treatment sample consisted of 73 consecutive patients diagnosed with PTSD according to the CAPS-5. According to the ITQ (n = 70) 33 (47.1%) patients also fulfilled the diagnostic criteria of Complex PTSD. The 4-day treatment programme contained a combination of prolonged exposure, EMDR therapy, physical activities and psycho-education. Treatment response was measured using the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5), the PTSD Checklist for DSM-5 (PCL-5), and the International Trauma Questionnaire (ITQ) for classifying Complex PTSD and indexing disturbances in self-organization (DSO). Results: Overall CAPS-5, PCL-5, and ITQ-DSO scores decreased significantly from pre- to post-treatment (Cohen’s ds 2.12, 1.59, and 1.18, respectively), while the decrease was maintained to six months follow-up. At post-treatment, 60 patients (82.2%) no longer met the diagnostic criteria of PTSD, while the proportion of patients with Complex PTSD decreased from 47.1% to 10.1%. No drop out, and no personal adverse events occurred. Conclusions: The results support the notion that intensive, trauma-focused treatment is feasible, safe and associated with a large decrease in PTSD and Complex PTSD symptoms, even when it is brief, and applied fully remote.