In order to determine the value of serum Gamma-glutamyltranspeptidase in the diagnosis of secondary hepatic malignancy, the variations of the serum measurement of different hepatic enzymes have been studied in 160 patients, 80 of which have hepatic metastases gamma GT showed an increase in 95% of the patients with metastases even if there has been a high percentage of false-positive results in the control patients and in those who were carriers of cancer without hepatic metastases. The Authors, after having briefly discussed the meaning of the false positivity rate, conclude that such an enzyme proves once to be a simple and sensitive test of secondary hepatic malignancy and that further studies will help to make it more specific.