Acute appendicitis is the most common surgical emergency of the abdomen and remains a diagnostic challenge despite advances in imaging techniques. Clinical evaluation supported by laboratory investigations, including white blood cell (WBC) count and neutrophil percentage, continues to play an important role in diagnosis. However, the diagnostic accuracy of these parameters remains variable. This prospective study aimed to evaluate the correlation between WBC count and neutrophil percentage in the diagnosis of acute appendicitis. A total of 147 patients clinically suspected of acute appendicitis and undergoing appendectomy between January 2017 and July 2018 were included. WBC count and neutrophil percentage were measured at admission, and final diagnosis was confirmed through histopathological examination. The sensitivity and specificity of WBC count were 72.7% and 73.3%, respectively, with positive and negative predictive values of 23.4% and 96%. Neutrophil percentage showed a sensitivity of 50.8% and specificity of 80%, with positive and negative predictive values of 15.6% and 95.7%, respectively. Histopathological confirmation of appendicitis was observed in 89.79% of cases. The findings suggest that WBC count and neutrophil percentage are useful supportive diagnostic tools when combined with clinical evaluation. However, they should not be used as standalone diagnostic indicators due to their variable sensitivity and specificity.