Background and aims: Acute appendicitis is an intra abdominal inflammation that manifests as pain in the right lower quadrant (RLQ) of abdomen which can develop into an acute abdomen. This situation could be ended up in the emergency room and require immediate surgical management. Ultrasonography (USG) imaging is the most common choice in appendicitis case to establish whether the surgical procedure on the patient is needed or not. The aim of this study was to determine the sensitivity and spesificity of USG on patient with suspected acute appendicitis. Methods: Research design of this study is Diagnostic Test of ultrasound examination compared with the gold standard which is results of histopathology examination. The study used secondary data on 2014-2017 taken from PKU Muhammadiyah Yogyakarta Hospital, PKU Muhammadiyah Gamping Hospital and Asri Medical Center. Results: From 71 data, positive ultrasound was 52 and negative ultrasound was 19. Fifty-two positive ultrasound found 29 adult patients and 23 pediatric patients with male sex equality were more dominant. Nineteen negative ultrasound shows 8 adult patients and 11 pediatric patients with female sex equality more dominant. The value of the diagnostic test obtained the sensitivity value and specificity value of USG was 82.7% and 33.33%. Conclusion: Ultrasound has good sensitivity value in assessing acute appendicitis and has a low specificity values in assessing acute appendicitis.