Focused assessment with sonography for trauma (FAST) has been incorporated into the initial evaluation of trauma for decades. It is an important screening tool in the detection of intra-abdominal fluid. The objective of this study was to perform a systematic review of the use and accuracy of FAST as an imaging tool for blunt abdominal trauma in disaster/mass casualty settings. A systematic review of literature was conducted using key words and search terms. Two independent reviewers screened abstracts to determine inclusion using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS). For studies passing QUADAS, a meta-analysis was performed calculating sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). FAST results were compared with the gold standard, which was a combination of CT scan results, operative findings, and medical records of the clinical course. Initial database screening resulted in 133 articles, of which 21 were selected for QUADAS evaluation. Five studies passed QUADAS and were selected in the final meta-analysis, with a total of 4263 patients. The sensitivity of FAST was 92.1% (87.8–95.6), specificity 98.7% (96.0–99.9), PPV 90.7% (70.0–98.0), and NPV 98.8% (98.1–99.5) for the detection of intra-abdominal injury. In our meta-analysis, FAST was both sensitive and specific in the evaluation of trauma in the disaster setting.