This paper reviews the history, technique, applications, advantages, disadvantages and complications of percutaneous needle aspiration biopsy. This technique, particularly when performed with a time needle (21-gauge or less), is a relatively painless, inexpensive and safe method of obtaining a pathologic diagnosis, and it can often be carried out at the bedside or in the outpatient department. It complements other methods and may obviate, but never precludes, subsequent excisional biopsy. Its advantages are insufficiently recognized. Considerable expertise of the cytopathologist and close cooperation with the clinician are necessary for consistent results.