Necropsies of Gavia immer (Common Loon) recovered lead and non-lead foreign objects from gastrointestinal tracts. Carcasses collected between 1987 and 2000 reveal that a great deal of loon mortality on lakes in New England is attributable to ingestion of lead objects. In this study, 522 carcasses were examined to inspect the types, sizes, and masses of 222 objects responsible for lead toxicosis. Most ingested lead objects were less than 2.5 cm long and weighed less than 25 g. Information on objects ingested by loons may help in development of non-toxic alternatives.