Each year 34 billion pounds of nylon carpet are discarded into landfills in the United States. As a case study we examine the technical and economic feasibility of recycling a portion of this source of discarded plastic. The carpet could be (I) shredded for use as daily cover at landfills or as a strengthening component of concrete, (2) sheared or chemically processed for reuse as recycled nylon or as pure nylon feedstock, or (3) made into a new type of plastic. We estimate the costs of a recycling facility to handle 450,000 Ib of discarded nylon carpet each month in Pittsburgh, Pennsylvania. We found that with current technology, regulations, and markets, only the recycling of carpet from commercial settings using shearing or chemical processing is economical and only under very narrow circumstances. We learned four lessons from this study, First, collection costs are high and can dominate the economics of recycling. Second, given time and incentives, collection costs can be reduced. Third, trying to recycle products not designed to be recycled leads to many problems. Carpet could be redesigned to make recycling easier by making the carpet out of a single material and using an adhesive that can be removed easily. Fourth, recycling processes should be designed to produce an existing material if at all possible, because new materials present marketing problems.