FNA biopsy is a quick, safe, and inexpensive method for obtaining material for pathological diagnosis. It is most useful in the diagnosis of a malignant tumor. In experienced hands it is highly accurate, and many of the pitfalls in cytological interpretation can be avoided with increased practice. Special training is required to become proficient in both obtaining and interpreting aspirated material. It is not sufficient for pathologists to apply personal experience from tissue pathology to the diagnosis of cytological specimens. Current indications are the FNA biopsy will be used with increasing frequency for reasons involving both clinical practice and cost containment.