ABSTRACT: The value of Ultrasonography (US) and HIDASCANNING (HIDA) in the diagnosis of Acute Cholecystitis, which may cause morbidity and mortality due to delays in diagnosis and treatment, has been investigated in this study. 92 patients have been monitored prospectively between January 1988 and January 1992. In our series, US had 86.95% accuracy, 88.63% sensitivity, 50% specificity; HIDA had 98.97% accuracy, 100% sensitivity, 75% specificity. Accuracy (p