Background: Clinical examination, Ultrasonography, and inflammatory indicators are used in the Tzanakis scoring system. By the application of this reliable Ultrasound-based score for diagnosing acute appendicitis, the process of decision making has improved. Hence, the present study was conducted to assess the usefulness of Tzanakis score in the diagnosis of acute appendicitis. Material &methods: The present cross-sectional study was conducted over a period of six months to assess the usefulness of Tzanakis score in the diagnosis of acute appendicitis. 50 patients were included in the study. The clinical diagnosis of acute appendicitis was made; the elements of Tzanakis score were recorded in every patient. All the data collected through the proforma were entered into the Statistical Package for Social Sciences (SPSS) version 18.0 and analyzed. The value of p<0.05 was considered statistically significant. Results: True Positive cases of acute appendicitis on histopathology were 38 and Tzanakis score diagnosed 37 cases of acute appendicitis. True positive were 33, false positive 4, false negative 5, and true negative were 8. Sensitivity of Tzanakis score in diagnosing acute appendicitis was 86.42%, specificity 66.66%, positive predictive value 89.18%, negative predictive value 61.53% and diagnostic accuracy was 76%. Conclusion: The present study concluded that diagnostic accuracy of Tzanakis score to diagnose acute appendicitis was 76%. Therefore, Tzanakis score at a cut-off total score of 8 is a very useful tool to diagnose acute appendicitis. Keywords: Diagnostic accuracy, Tzanakis score, acute appendicitis.