Background: Acute appendicitis is a disease with a well-known long history. The final diagnosis of acute appendicitis is only accurate with histopathological findings after appendectomy. However, the choice to carry out surgical treatment is based exclusively on clinical assessment which does not reach the precise diagnosis of appendicitis. Therefore, Different scoring systems have emerged in order to help physicians in decision making and diagnosis of suspicious individuals. Aim: To determine the diagnostic accuracy of the Modified Alvarado Scoring System in a low-income country in the diagnosis of appendicitis. Patients and Methods: This was a cross-sectional study that included 200 patients with right iliac fossa pain, suggestive of acute appendicitis. The patients were examined clinically and randomly allocated into 2 groups. The Modified Alvarado Scoring System (MASS) was calculated for the case group and listed and compared to another control group for which the operative decision was based on the clinical evaluation without relying on a scoring system. All the studied patients went through appendectomy according to overall clinical judgment and never based on MASS only. Specimens were sent to histopathological examination to verify the diagnosis. Results: The results showed that MASS at the cut-off value of ≥ 7 has a sensitivity of 93.33%, a specificity of 52.94%, and accuracy of 84.42%, and a negative appendectomy rate of 17 out of 95 patients (17.8%). Conclusion: MASS is a safe tool in the diagnosis of acute appendicitis due to its accepted sensitivity and higher specificity. It could be helpful in low-income countries, where resources are limited.