The paper discusses the design and initial operation of the U.S. Environmental Protection Agency's (EPA) Mobile Volume Reduction Unit (VRU) for soil washing. Soil washing removes contaminants from soils by dissolving or suspending them in the wash solutions (which can be later treated by conventional waste water treatment methods) or by volume reduction through simple particle size separation techniques. Contaminants are primarily concentrated in the fine-grained (<0.063 mm, 0.0025) inch soil fraction. The VRU is a pilot-scale mobile system for washing soil contaminated with a wide variety of heavy metal and organic contaminants. The unit includes state-of-the-art washing equipment for field applications.