The value of biochemical methods, scintigraphy and sonography in the diagnosis of liver metastases was compared in 150 patients. Of the laboratory methods, gamma-GT proved the most suitable screening method. A negative scan was of considerable value in excluding liver metastases. Positive findings are not always definite and require confirmation. Ultrasound, because of its high accuracy, is the most valuable method for excluding or demonstrating liver metastases. Suggestions for diagnostic procedures are made as a result of these findings.