Fine needle aspiration (F.N.A.) is widely accepted as a safe and reliable diagnostic technique. In patients presenting with widespread metastatic disease of unknown primary origin it can play an important role in providing a rapid and accurate diagnosis and therefore allowing to institute a prompt therapeutic approach. This technique can usually be performed in an outpatient setting needing no hospitalization therefore reducing the cost both for the hospital and for the patient. When a definitive diagnosis is reached with the use of F.N.A. the patient can be spared from unnecessary surgery. A few examples are presented of patients with widespread metastatic disease in which a definitive diagnosis was reached through the use of F.N.A.