Background and Aims Acute appendicitis is one of the most common causes of lower abdominal pain, which is considered a general surgical emergency worldwide. The present study aimed to compare the diagnostic value of Raja Isteri Pengiran Anak Saleha Appendicitis (RIPASA) and Alvarado score systems in diagnosing acute appendicitis. Methods A prospective cross‐sectional study was conducted at Shahid Sadoughi and Shahid Rahnemoon Hospitals in Yazd between September 2020 and February 2020. The statistical population consisted of all of the patients referred to the Accident and Emergency department with right iliac fossa (RIF) pain. All patients were scored using Alvarado and RIPASA scoring system. sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were computed by using SPSS statistical software. An receiver operating characteristic curve were plotted. Results In present study, one hundred suspected patients with appendicitis who underwent appendectomy were evaluated. The mean age of our study population was 25.2 ± 12.1 years, and the gender distribution was 57% males and 43% females. The sensitivity, specificity, PPV and NPV of RIPASA were 86.6%, 66.7%, 92.2%, and 52.2%, respectively. The sensitivity, specificity, PPV and NPV of Alvarado score were 67.1%, 72.2%, 91.7%, 32.5%, respectively. The diagnostic accuracy was 68% for Alvarado score and 83% for RIPASA. The area under the curve for RIPASA (0.87) was more than that for Alvarado score (0.77). Conclusion The RIPASA score system had higher sensitivity, PPV, NPV, and accuracy than the Alvarado one. It is recommended for the physician and surgeon to evaluate patients with RIF pain using the RIPASA score.