Fine needle aspiration biopsy (FNAB) is a diagnostic test routinely used in the evaluation of thyroid nodule disease and it is crucial to stratify the risk of malignancy. Furthermore, FNAB can also be used to evacuate large cystic nodules and is helpful in patient with thyroid cancer to detect lymph nodes metastases. FNAB is a minimally invasive procedure with low risks and can be usually performed on an outpatient basis by experienced physicians. It is fundamental to obtain an adequate signed consent after the patient has been fully informed. US guidance is routinely used. Biopsy specimens may be obtained with two widely used acquisition methods. The choice between “nonaspiration” and “aspiration” is a matter of operator preference. The only serious contraindication is hemorrhagic diathesis.