Wetlands have a well-documented capacity for extracting metals, particularly uranium, from ground and surface waters containing only very dilute concentrations of the metals. The plutonic and volcanic rocks of the Colorado Rockies contain uranium concentrations high enough to serve as a uranium source to waters that feed wetlands. Reconnaissance sampling was conducted in 145 montane and subalpine wetlands in Colorado to determine how many of them are uraniferous. Forty-six percent of the wetlands showed the presence of moderate or high concentrations of uranium, but unless the price of uranium substantially increases none of the deposits is of economic value. Many of the processes responsible for concentrating uranium and other metals in organic-rich sediments of wetlands are reversible, however, and serious environmental consequences may occur if anthropogenic or natural disturbances change the chemical conditions in a wetland sufficiently to release uranium or other metals.