The serum tumor markers are often required in an appropriate way as they need a simple blood sample. Given the high cost of each prescription tests and the high number of required tests it represents a considerable employment of resources; in addition it represents a source of anxiety for the patient in the case of a false positive result. Their inappropriate use in asymptomatic patients, in the presence of a test higher than normal, often require further diagnostic tests and medical and surgical inappropriate treatments. In diagnostic setting these markers can be considered only in well-defined types of malignancies, not particularly frequent (hepatocellular carcinoma, testicular tumors, pancreatic cancer). Tumour markers may be indicated only as therapy monitoring and follow-up of patients with ascertained diagnosis of neoplasia, only in the cases that are established by specific guidelines.