Tumour markers are biochemical indicators of the presence of a tumour, which are selectively produced by the neoplastic tissue and released into blood or in other body fluids. They are widely accepted and applied to the management of patients with cancer since the introduction of diagnostic immunopathology. Tumour markers include oncofetal antigens (AFP), glycoproteins (CEA), placental proteins (PLAP), hormones (ACTH and HCG), enzymes (PSA and PAP) and other molecular species. Monoclonal antibody technique is the most commonly used method for identification of specific marker in tissue, urine or blood sample. Assay of various tumour markers can be used for population screening, tumour detection, diagnosis, staging, prognosis or follow up of malignant diseases.