A comparative study has been realized to test the accuracy of ultrasonography and scintigraphy for detecting the presence of liver metastases in 305 patients with colorectal carcinomas. Presence or absence of hepatic metastases has been affirmed by laparotomy and biopsy. In the 47 cases with metastases, the sensitivity of ultrasonography was 93%, that of scintigraphy being 76%. In 258 cases without metastases the specificity of ultrasonography was 97%, that of scintigraphy being 92%. These results, confirmed by report in the published literature, show that ultrasonography should be the first examination for suspected hepatic metastases.