Twenty-seven patients with clinically suspected acute cholecystitis were prospectively evaluated for supporting evidence with intravenous cholangiography and gray scale sonography. Twenty of these fulfilled criteria for inclusion in the study. Sonography was found to be helpful in all 20 patients (100%). Intravenous cholangiography could be performed in 16 patients (four patients had elevated bilirubin greater than 4 mg/dl). Of these 16, cholangiography was diagnostic in nine (56.3% accuracy). Because of the superiority of sonography and the morbidity and mortality associated with intravenous cholangiography, the study was terminated. Consequently, it is believed sonography is superior to intravenous cholangiography in the evaluation of suspected acute cholecystitis.