Four cases of resected adenosquamous carcinoma of the liver were clinicopathologically reviewed, together with immunohistochemical findings. Although no lymph node metastases were seen and a curative resection was achieved in all cases, two patients had recurrences in the peritoneum and distant organs such as the pericardium and pleura relatively soon after the operation. Of the remaining two cases, one patient died during the postoperative period and the other died of coexistent hilar cholangiocarcinoma. Together these findings suggest that this disease tends to spread locally and distantly in the early phase of tumor growth and shows aggressive biological behavior. In an immunohistochemical study, involucrin was a specific marker for the squamous component and CA19-9 was a marker for the adenomatous component.