Background: The use of the Alvarado scoring system as a tool for diagnosing acute appendicitis has been associated with a reduction of negative appendicectomies. This study aimed to assess the diagnostic accuracy of the Alvarado scoring system at predicting acute appendicitis in patients undergoing appendicectomy at the University Teaching Hospital (UTH). Methods: A prospective study was done to evaluate the diagnostic value of the Alvarado score in patients undergoing appendicectomy at the UTH. Data was collected from the participants diagnosed with acute appendicitis and undergoing appendicectomy. The Alvarado scores for all the participants enrolled into the study were tabulated and correlated with the histopathology results. The sensitivity and the specificity of the Alvarado score was determined and used to construct the ROC curve using the SPSS version 20. The area under the curve was used to determine the diagnostic accuracy of the Alvarado score in this study. Setting: The University Teaching Hospital in Lusaka, Zambia. Results: To determine the diagnostic accuracy of the Alvarado score the ROC curve test was run in SPSS version 20. The results showed that the area under the curve was C=0.842 with SE=0.047 and 95% CI from 0.750 to 0.934. The area under the curve represents the probability that the Alvarado score result for a randomly chosen positive case will exceed the result for a randomly chosen negative case. It shows from the ROC that the Alvarado score is a good indicator to anticipate acute appendicitis. In other words, these results have confirmed that the Alvarado scoring system has very high predictive ability to discriminate acute appendicitis from normal appendix subjects. Conclusion: The use of the Alvarado scoring system as a tool for diagnosing acute appendicitis at UTH will reduce the rate of negative appendicectomies. This will lead to a reduction in unnecessary operations, which are a burden on the health care system.