Sacroiliac screw fixation is the method of choice for the definitive treatment of unstable posterior pelvic ring injuries; however this technique is demanding and associated with a high risk of iatrogenic neurovascular damage. We therefore evaluated the outcome, complications, surgical and fluoroscopy time for unstable posterior pelvic ring injuries managed with a transiliac locked compression plate. 23 patients were managed with a transiliac locked compression plate for unstable posterior pelvic injuries at a Level I Trauma Center. 21 patients were available for follow up after an average of 30 months and outcome evaluation was performed with the Pelvic Outcome Score, which is composed of a clinical, radiological, and social integration part. The overall outcome for the pelvic outcome score was excellent in 47.6% (10 patients), good in 19% (4 patients), fair in 28.6% (6 patients) and poor in 4.8% (1 patient). 15 out of 21 patients (71.4%) returned to their normal life, 3 patients (14.3%) were limited at work, and 3 patients (14.3%) were not able to return to work due to their disabilities. The social status was unchanged to the preinjury status in 19 patients (90.5%). 13 patients (62%) stated no changes in spare time and sports activities; 4 patients (19%) had minor and another 4 patients (19%) had major restrictions. The average operation time was 101 min and intraoperative fluoroscopic time averaged 74.2 sec. No iatrogenic neurovascular injuries were observed. Posterior percutaneous plate osteosynthesis may be a good alternative to sacral screw fixation because it is quick, safe, and associated with a good functional outcome.