Head and neck cancers are a major heath problem and common malignancies in Thailand. Up to 80 per cent of cases are caused by smoking and alcohol consumption. Epithelial mucosa of the aerodigestive tract exposed to carcinogens results in cellular mutations at different areas by a process called field cancerization and causes multistep carcinogenesis. Over 90 per cent of cases are squamous cell carcinoma. Prognostic factors depend on the patients, diseases and treatment. Currently, several molecular pathogenesis have been discovered such as abnormalities of c-myc, c-ras, c-erbB-1, bcl, int-2, hst1 oncogenes, p53 and p16 tumor suppressor genes. Common chromosomal abnormalities are 3p, 9p, 11q, 13q, 17p. Diagnosis requires symptoms and signs, radioimaging, and pathology. Stage I and II can be treated by surgery or radiotherapy. However, stage II requires and combination of surgery and radiotherapy, and studies of chemotherapy and local treatment to increase therapeutic efficacy by several approaches such as combination chemotherapy, new drugs, and biologic therapy.