Radioimmunoscintigraphy (RIS) of colorectal carcinomas is under investigation in controlled clinical studies in Germany since 1985. With the availability of 99mTc labelled monoclonal antibodies against the carcinoembryonic antigen (CEA), there is an increasing acceptance of this new technique; nevertheless, the merits of RIS in comparison to established methods of staging and restaging of patients with colorectal carcinomas as computed tomography, endoscopy and sonography are still under discussion. In this review the current "State of the Art" of radioimmunoscintigraphy of colorectal carcinomas is given in respect of whether there is additional information which can be gained only by Ris but not by the established diagnostic procedure.