Background: The purpose of this study is to define the sensitivity and specificity of the gallbladder ejection fraction (GBEF) for identifying patients with various grades of histologically proven chronic cholecystitis. Methods. Of 693 consecutive patients who had a scintigraphic GBEF determination at Baptist Medical Center of Oklahoma, 161 subsequently had a cholecystectomy at the same institution. Pathologic material was reassessed by one outside blinded reviewer, who graded the intensity of the inflammation present on a 0 (absent) to 3 (most severe) scale. Results. The least square mean maximum GBEF was 23.7% for those with grade 0, 9.6% for those with grade 3, and 13.9% for those with cholesterolosis. If a normal value for GBEF is set at >30%, the sensitivity for detecting grade 1, 2, or 3 disease was 84%, and the specificity was 26%. For grade 3 disease alone, the sensitivity was 100%, and the specificity was 26%. Conclusions. The GBEF is sensitive but not specific for chronic inflammation of the gallbladder. The GBEF appears to be useful as a screening examination in the appropriate clinical setting.