Inasmuch as terrestrial fauna are an integral part of our natural environment and are directly exposed to disease and pollutants, it follows that certain wild populations could serve to detect subtle alterations within ecosystems. A collection of studies on raccoons is presented to stimulate other researchers to develop the potential of our wildlife resources as monitors of environmental health. Raccoons have been used as serologic sentinels for St Louis encephalitis and Venezuelan equine encephalomyelitis. Studies suggest that the raccoon may be used as an indicator of leptospirosis, tularemia, and some enteric bacteria and viruses. Base line surveys have defined (1) residue levels of organochlorine and organophosphate compounds and (2) body burdens of mercury, cesium-137, and strontium-90. Physiologic responses, parasite burdens, and reproductive processes are also considered as measures that may reflect pertinent information about environmental health.