Endosonography was performed preoperatively in 46 patients with carcinoma of the common hepatic duct and its bifurcation. The results of endosonography were correlated with findings during surgery and pathological examination of the resected specimen and classified according to the new (1987) TNM classification. Overall accuracy in assessing the depth of tumor infiltration was 86.0%. Endosonography was accurate in predicting the presence of lymph nodes but not accurate in defining non-metastatic changes of lymph nodes. Staging of distant metastases was not accurate due to the low penetration depth of ultrasound.