Two cases of infected false aneurysms of the subclavian artery in drug addicts are described. The clinical findings related to the location of these rare lesions are presented, together with an attempt to explain their pathophysiology. The signs and symptoms include a tender supraclavicular mass in an obviously septic patient associated with brachial plexus palsy, a swollen edematous arm, Horner's syndrome, and hemoptysis. Because of the complexity of symptoms, delay in diagnosis is common. It is emphasized that the recognition of this constellation of symptoms should prompt the physician to perform emergency angiography followed by immediate surgery.