Twenty-three ospreys (Pandion haliaetus) found dead or moribund in the eastern United States during 1975–1982 were necropsied and selected tissues were analyzed for organo-chlorines and metals. Major causes or factors contributing to death were trauma, impact injuries, and emaciation. DDE was detected in 96% of the osprey carcasses, DDD in 65%, DDT and heptachlor epoxide in 13%, dieldrin, oxychlordane, and cis-nonachlor in 35%, cis-chlordane in 52%, trans-nonachlor in 45%, and PCB's in 83%. Carcasses of immature ospreys from the Chesapeake Bay had significantly lower concentrations of DDE, DDD DDT, cis-chlordane, and PCB's than carcasses of adults from the same area. Concentrations of some organochlorines in ospreys from the Chesapeake Bay declined significantly from 1971–1973 to 1975–1982. Significant differences in concentrations of certain metals in the ospreys' livers were noted between time periods, and sex and age groups for birds from the Chesapeake Bay. During 1975–1982, adults had significantly lower concentrations of chromium, copper, and arsenic than immatures and nestlings, and adult males had higher mercury concentrations than adult females. Adult females had lower zinc concentrations in 1975–1982 than in 1971–1973. Immatures and nestlings had higher concentrations of chromium and lead in 1975–1982 than in 1971–1973. A slightly elevated concentration of chromium (1.7 ppm) or arsenic (3.2 ppm) was found in the livers of individual ospreys. Several ospreys had elevated concentrations of mercury in their livers; two ospreys had more than 20 ppm which may have contributed to their deaths.