Immunohistology of CEA has been used now for many years in research and in diagnostic applications. In this congress paper, the need for specificity checks, correct preservation and quality control of antibodies as well as the choice and preservation of control tissues will be discussed and, in addition, some aspects of the interpretation of CEA immunohistology in surgical pathology are illustrated, based upon prospectively collected data from a routine surgical pathology unit. An approach for collection and analysis is demonstrated and the diagnostic importance of CEA expression together with other antigens in the same tumor.