Acute appendicitis is the most common surgical abdominal emergency. Its clinical diagnosis remains a challenge to surgeons, so different imaging options were introduced to improve diagnostic accuracy. Among these imaging modality choices, diagnostic medical sonography (DMS) is a simple, easily available, and cost effective clinical tool. The purpose of this study was to assess the accuracy of DMS, in the diagnosis of acute appendicitis compared to the histopathology report, as a gold standard. Between May 2015 and May 2016, 215 patients with suspected appendicitis were examined with DMS. The DMS findings were recorded as positive and negative for acute appendicitis and compared with the histopathological results, as a gold standard. In all, 173 patients were correctly diagnosed as having acute appendicitis by DMS out of 200 cases, with a final histopathologic result. Similarly, DMS revealed 13 normal appendices out of 15 nonappendicitis patients. This demonstrated that DMS has a sensitivity of 86.5%, specificity of 86.6%, positive predictive value of 99.8%, negative predictive value of 32.5%, and overall accuracy of 86.5%. These results suggest that DMS may be an accurate, sensitive, and specific tool for diagnosing acute appendicitis and reducing unnecessary appendectomies. DMS should be considered as a credible imaging modality for diagnosing acute appendicitis.