The diagnosis of acute appendicitis is a clinical challenge. Clinical scoring systems and radiological examinations are used to assist in diagnosis. We reviewed 106 patients between January 2016 and January 2018 who presented with right iliac fossa pain and underwent appendectomy. Their Raja Isteri Pengiran Anak Saleha Appendicitis (RIPASA) scores were calculated and abdominopelvic ultrasonography (USG) was performed before they were operated with a prediagnosis of acute appendicitis. RIPASA scores and USG findings were compared to the histopathological results of appendectomy specimens. The histopathological examinations showed that all of the 100 (94.3%) patients whose RIPASA scores were 7 and more had acute appendicitis and the six (5.7%) patients whose scores were less than 7 had no appendicitis. When the appendectomy specimens of the 70 patients who had been diagnosed with acute appendicitis with USG were examined histopathologically, 69 (98.6%) patients were confirmed to have acute appendicitis. Acute appendicitis was found in 18 (81.8%) of the 22 patients whose appendixes could not be visualized with USG. Acute appendicitis was found in eight (88.9%) of the nine patients who had been reported normal with USG. RIPASA scores should be calculated for all patients who are suspected of having acute appendicitis and for those with a RIPASA score of 7 and more, surgery should be highly recommended without USG.